diff --git a/src/all.bash b/src/all.bash
index d80a09d1162..932b65dc070 100755
--- a/src/all.bash
+++ b/src/all.bash
@@ -9,5 +9,5 @@ if [ ! -f make.bash ]; then
 	exit 1
 fi
 . ./make.bash --no-banner
-bash run.bash --no-rebuild
-../bin/tool/dist banner  # print build info
+bash run.bash --no-rebuild --banner
+$GOTOOLDIR/dist banner  # print build info
diff --git a/src/cmd/dist/a.h b/src/cmd/dist/a.h
index e90f7fe65d8..3fbace3f6d2 100644
--- a/src/cmd/dist/a.h
+++ b/src/cmd/dist/a.h
@@ -72,7 +72,9 @@ extern char *goroot;
 extern char *goroot_final;
 extern char *goversion;
 extern char *workdir;
+extern char *tooldir;
 extern char *slash;
+extern bool rebuildall;
 
 int	find(char*, char**, int);
 void	init(void);
diff --git a/src/cmd/dist/build.c b/src/cmd/dist/build.c
index c8984300b09..72097230a11 100644
--- a/src/cmd/dist/build.c
+++ b/src/cmd/dist/build.c
@@ -13,15 +13,19 @@
 char *goarch;
 char *gobin;
 char *gohostarch;
+char *gohostchar;
 char *gohostos;
 char *goos;
 char *goroot = GOROOT_FINAL;
 char *goroot_final = GOROOT_FINAL;
 char *workdir;
+char	*tooldir;
 char *gochar;
 char *goversion;
 char *slash;	// / for unix, \ for windows
 
+bool	rebuildall = 0;
+
 static bool shouldbuild(char*, char*);
 static void copy(char*, char*);
 static char *findgoversion(void);
@@ -99,14 +103,18 @@ init(void)
 	if(b.len > 0)
 		gohostarch = btake(&b);
 
-	if(find(gohostarch, okgoarch, nelem(okgoarch)) < 0)
+	i = find(gohostarch, okgoarch, nelem(okgoarch));
+	if(i < 0)
 		fatal("unknown $GOHOSTARCH %s", gohostarch);
+	bprintf(&b, "%c", gochars[i]);
+	gohostchar = btake(&b);
 
 	xgetenv(&b, "GOARCH");
 	if(b.len == 0)
 		bwritestr(&b, gohostarch);
 	goarch = btake(&b);
-	if((i=find(goarch, okgoarch, nelem(okgoarch))) < 0)
+	i = find(goarch, okgoarch, nelem(okgoarch));
+	if(i < 0)
 		fatal("unknown $GOARCH %s", goarch);
 	bprintf(&b, "%c", gochars[i]);
 	gochar = btake(&b);
@@ -124,6 +132,9 @@ init(void)
 	workdir = xworkdir();
 	xatexit(rmworkdir);
 
+	bpathf(&b, "%s/pkg/tool/%s_%s", goroot, gohostos, gohostarch);
+	tooldir = btake(&b);
+
 	bfree(&b);
 }
 
@@ -256,6 +267,7 @@ static char *oldtool[] = {
 	"8a", "8c", "8g", "8l",
 	"6cov",
 	"6nm",
+	"6prof",
 	"cgo",
 	"ebnflint",
 	"goapi",
@@ -281,11 +293,8 @@ setup(void)
 
 	binit(&b);
 
-	// Create tool directory.
+	// Create bin directory.
 	p = bpathf(&b, "%s/bin", goroot);
-	if(!isdir(p))
-		xmkdir(p);
-	p = bpathf(&b, "%s/bin/tool", goroot);
 	if(!isdir(p))
 		xmkdir(p);
 
@@ -293,21 +302,42 @@ setup(void)
 	p = bpathf(&b, "%s/pkg", goroot);
 	if(!isdir(p))
 		xmkdir(p);
-	p = bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch);
-	xremoveall(p);
+	p = bpathf(&b, "%s/pkg/%s_%s", goroot, gohostos, gohostarch);
+	if(rebuildall)
+		xremoveall(p);
 	xmkdir(p);
-
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch)) {
+		p = bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch);
+		if(rebuildall)
+			xremoveall(p);
+		xmkdir(p);
+	}
+	
 	// Create object directory.
 	// We keep it in pkg/ so that all the generated binaries
-	// are in one tree.
-	p = bpathf(&b, "%s/pkg/obj", goroot);
-	xremoveall(p);
-	xmkdir(p);
+	// are in one tree.  If pkg/obj/libgc.a exists, it is a dreg from
+	// before we used subdirectories of obj.  Delete all of obj
+	// to clean up.
+	bpathf(&b, "%s/pkg/obj/libgc.a", goroot);
+	if(isfile(bstr(&b)))
+		xremoveall(bpathf(&b, "%s/pkg/obj", goroot));
+	p = bpathf(&b, "%s/pkg/obj/%s_%s", goroot, gohostos, gohostarch);
+	if(rebuildall)
+		xremoveall(p);
+	xmkdirall(p);
+
+	// Create tool directory.
+	// We keep it in pkg/, just like the object directory above.
+	xremoveall(tooldir);
+	xmkdirall(tooldir);
+
+	// Remove tool binaries from before the tool/gohostos_gohostarch
+	xremoveall(bpathf(&b, "%s/bin/tool", goroot));
 
 	// Remove old pre-tool binaries.
 	for(i=0; i<nelem(oldtool); i++)
-		xremove(bprintf(&b, "%s%s%s%s%s", goroot, slash, "bin", slash, oldtool[i]));
-	
+		xremove(bpathf(&b, "%s/bin/%s", goroot, oldtool[i]));
+
 	// If $GOBIN is set and has a Go compiler, it must be cleaned.
 	for(i=0; gochars[i]; i++) {
 		if(isfile(bprintf(&b, "%s%s%c%s", gobin, slash, gochars[i], "g"))) {
@@ -390,37 +420,37 @@ static struct {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../5l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/6c", {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../6l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/8c", {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../8l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/5g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../5l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/6g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../6l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/8g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../8l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/5l", {
 		"../ld/data.c",
@@ -442,9 +472,9 @@ static struct {
 		"enam.c",
 	}},
 	{"cmd/", {
-		"$GOROOT/pkg/obj/libmach.a",
-		"$GOROOT/pkg/obj/libbio.a",
-		"$GOROOT/pkg/obj/lib9.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libmach.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libbio.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/lib9.a",
 	}},
 	{"pkg/runtime", {
 		"zasm_$GOOS_$GOARCH.h",
@@ -490,8 +520,12 @@ install(char *dir)
 	Time ttarg, t;
 	int i, j, k, n, doclean;
 
-	if(vflag)
-		xprintf("%s\n", dir);
+	if(vflag) {
+		if(!streq(goos, gohostos) || !streq(goarch, gohostarch))
+			xprintf("%s (%s/%s)\n", dir, goos, goarch);
+		else
+			xprintf("%s\n", dir);
+	}
 
 	binit(&b);
 	binit(&b1);
@@ -521,7 +555,7 @@ install(char *dir)
 
 	islib = hasprefix(dir, "lib") || streq(dir, "cmd/cc") || streq(dir, "cmd/gc");
 	ispkg = hasprefix(dir, "pkg");
-	isgo = ispkg || streq(dir, "cmd/go");
+	isgo = ispkg || streq(dir, "cmd/go") || streq(dir, "cmd/cgo");
 
 	exe = "";
 	if(streq(gohostos, "windows"))
@@ -536,27 +570,30 @@ install(char *dir)
 		prefix = "";
 		if(!hasprefix(name, "lib"))
 			prefix = "lib";
-		vadd(&link, bpathf(&b, "%s/pkg/obj/%s%s.a", goroot, prefix, name));
+		vadd(&link, bpathf(&b, "%s/pkg/obj/%s_%s/%s%s.a", goroot, gohostos, gohostarch, prefix, name));
 	} else if(ispkg) {
 		// Go library (package).
-		vadd(&link, bpathf(&b, "%s/bin/tool/pack", goroot));
+		vadd(&link, bpathf(&b, "%s/pack", tooldir));
 		vadd(&link, "grc");
-		p = bprintf(&b, "%s/pkg/%s_%s/%s", goroot, goos, goarch, dir+4);
+		p = bprintf(&b, "%s/pkg/%s_%s/%s", goroot, gohostos, gohostarch, dir+4);
 		*xstrrchr(p, '/') = '\0';
 		xmkdirall(p);
-		vadd(&link, bpathf(&b, "%s/pkg/%s_%s/%s.a", goroot, goos, goarch, dir+4));
-	} else if(streq(dir, "cmd/go")) {
+		vadd(&link, bpathf(&b, "%s/pkg/%s_%s/%s.a", goroot, gohostos, gohostarch, dir+4));
+	} else if(streq(dir, "cmd/go") || streq(dir, "cmd/cgo")) {
 		// Go command.
-		vadd(&link, bpathf(&b, "%s/bin/tool/%sl", goroot, gochar));
+		vadd(&link, bpathf(&b, "%s/%sl", tooldir, gochar));
 		vadd(&link, "-o");
-		vadd(&link, bpathf(&b, "%s/bin/tool/go_bootstrap%s", goroot, exe));
+		elem = name;
+		if(streq(elem, "go"))
+			elem = "go_bootstrap";
+		vadd(&link, bpathf(&b, "%s/%s%s", tooldir, elem, exe));
 	} else {
 		// C command.
 		// Use gccargs, but ensure that link.p[2] is output file,
 		// as noted above.
 		vadd(&link, gccargs.p[0]);
 		vadd(&link, "-o");
-		vadd(&link, bpathf(&b, "%s/bin/tool/%s%s", goroot, name, exe));
+		vadd(&link, bpathf(&b, "%s/%s%s", tooldir, name, exe));
 		vcopy(&link, gccargs.p+1, gccargs.len-1);
 		if(streq(gohostarch, "amd64"))
 			vadd(&link, "-m64");
@@ -636,7 +673,7 @@ install(char *dir)
 	}
 
 	// Is the target up-to-date?
-	stale = 1;  // TODO: Decide when 0 is okay.
+	stale = rebuildall;
 	n = 0;
 	for(i=0; i<files.len; i++) {
 		p = files.p[i];
@@ -682,12 +719,6 @@ install(char *dir)
 		copy(bpathf(&b, "%s/signals_GOOS.h", workdir),
 			bpathf(&b1, "%s/signals_%s.h", bstr(&path), goos));
 	}
-	
-	// For cmd/prof, copy pprof into the tool directory.
-	if(streq(dir, "cmd/prof")) {
-		copy(bpathf(&b, "%s/bin/tool/pprof", goroot),
-			bpathf(&b1, "%s/src/cmd/prof/pprof", goroot));
-	}
 
 	// Generate any missing files; regenerate existing ones.
 	for(i=0; i<files.len; i++) {
@@ -737,6 +768,13 @@ install(char *dir)
 		}
 		vuniq(&files);
 	}
+	
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch)) {
+		// We've generated the right files; the go command can do the build.
+		if(vflag > 1)
+			xprintf("skip build for cross-compile %s\n", dir);
+		goto nobuild;
+	}
 
 	// Compile the files.
 	for(i=0; i<files.len; i++) {
@@ -762,7 +800,7 @@ install(char *dir)
 			vadd(&compile, "-I");
 			vadd(&compile, bstr(&path));
 	
-			// runtime/goos.c gets the default constants hard-coded.
+			// lib9/goos.c gets the default constants hard-coded.
 			if(streq(name, "goos.c")) {
 				vadd(&compile, bprintf(&b, "-DGOOS=\"%s\"", goos));
 				vadd(&compile, bprintf(&b, "-DGOARCH=\"%s\"", goarch));
@@ -780,9 +818,9 @@ install(char *dir)
 		} else {
 			// Supporting files for a Go package.
 			if(hassuffix(files.p[i], ".s"))
-				vadd(&compile, bpathf(&b, "%s/bin/tool/%sa", goroot, gochar));
+				vadd(&compile, bpathf(&b, "%s/%sa", tooldir, gochar));
 			else {
-				vadd(&compile, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+				vadd(&compile, bpathf(&b, "%s/%sc", tooldir, gochar));
 				vadd(&compile, "-FVw");
 			}
 			vadd(&compile, "-I");
@@ -820,7 +858,7 @@ install(char *dir)
 		// The last loop was compiling individual files.
 		// Hand the Go files to the compiler en masse.
 		vreset(&compile);
-		vadd(&compile, bpathf(&b, "%s/bin/tool/%sg", goroot, gochar));
+		vadd(&compile, bpathf(&b, "%s/%sg", tooldir, gochar));
 
 		bpathf(&b, "%s/_go_.%s", workdir, gochar);
 		vadd(&compile, "-o");
@@ -853,6 +891,7 @@ install(char *dir)
 
 	runv(nil, nil, CheckExit, &link);
 
+nobuild:
 	// In package runtime, we install runtime.h and cgocall.h too,
 	// for use by cgo compilation.
 	if(streq(dir, "pkg/runtime")) {
@@ -921,6 +960,8 @@ shouldbuild(char *file, char *dir)
 	// so special case that file.
 	if(hassuffix(file, "cmd/go/doc.go") || hassuffix(file, "cmd\\go\\doc.go"))
 		return 0;
+	if(hassuffix(file, "cmd/cgo/doc.go") || hassuffix(file, "cmd\\cgo\\doc.go"))
+		return 0;
 
 	// Check file contents for // +build lines.
 	binit(&b);
@@ -940,7 +981,7 @@ shouldbuild(char *file, char *dir)
 			ret = 0;
 			goto out;
 		}
-		if(contains(p, "package main") && !streq(dir, "cmd/go")) {
+		if(contains(p, "package main") && !streq(dir, "cmd/go") && !streq(dir, "cmd/cgo")) {
 			ret = 0;
 			goto out;
 		}
@@ -1044,7 +1085,6 @@ static char *buildorder[] = {
 	"pkg/net/url",
 	"pkg/text/template/parse",
 	"pkg/text/template",
-
 	"cmd/go",
 };
 
@@ -1140,15 +1180,18 @@ clean(void)
 			xremove(bpathf(&b, "%s/%s", bstr(&path), cleantab[i]+4));
 	}
 
-	// Remove object tree.
-	xremoveall(bpathf(&b, "%s/pkg/obj", goroot));
+	if(rebuildall) {
+		// Remove object tree.
+		xremoveall(bpathf(&b, "%s/pkg/obj/%s_%s", goroot, gohostos, gohostarch));
 	
-	// Remove installed packages and tools.
-	xremoveall(bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch));
-	xremove(bpathf(&b, "%s/bin/tool", goroot));
-	
-	// Remove cached version info.
-	xremove(bpathf(&b, "%s/VERSION.cache", goroot));
+		// Remove installed packages and tools.
+		xremoveall(bpathf(&b, "%s/pkg/%s_%s", goroot, gohostos, gohostarch));
+		xremoveall(bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch));
+		xremoveall(tooldir);
+
+		// Remove cached version info.
+		xremove(bpathf(&b, "%s/VERSION.cache", goroot));
+	}
 
 	bfree(&b);
 	bfree(&path);
@@ -1212,7 +1255,11 @@ cmdenv(int argc, char **argv)
 	xprintf(format, "GOBIN", gobin);
 	xprintf(format, "GOARCH", goarch);
 	xprintf(format, "GOOS", goos);
+	xprintf(format, "GOHOSTARCH", gohostarch);
+	xprintf(format, "GOHOSTOS", gohostos);
+	xprintf(format, "GOTOOLDIR", tooldir);
 	xprintf(format, "GOCHAR", gochar);
+
 	if(pflag) {
 		sep = ":";
 		if(streq(gohostos, "windows"))
@@ -1233,8 +1280,14 @@ cmdbootstrap(int argc, char **argv)
 {
 	int i;
 	Buf b;
+	char *oldgoos, *oldgoarch, *oldgochar;
+
+	binit(&b);
 
 	ARGBEGIN{
+	case 'a':
+		rebuildall = 1;
+		break;
 	case 'v':
 		vflag++;
 		break;
@@ -1249,9 +1302,32 @@ cmdbootstrap(int argc, char **argv)
 	goversion = findgoversion();
 	setup();
 	
-	binit(&b);
-	for(i=0; i<nelem(buildorder); i++)
-		install(bprintf(&b, buildorder[i], gochar));
+	// For the main bootstrap, building for host os/arch.
+	oldgoos = goos;
+	oldgoarch = goarch;
+	oldgochar = gochar;
+	goos = gohostos;
+	goarch = gohostarch;
+	gochar = gohostchar;
+	xsetenv("GOARCH", goarch);
+	xsetenv("GOOS", goos);
+	
+	for(i=0; i<nelem(buildorder); i++) {
+		install(bprintf(&b, buildorder[i], gohostchar));
+		if(!streq(oldgochar, gohostchar) && xstrstr(buildorder[i], "%s"))
+			install(bprintf(&b, buildorder[i], oldgochar));
+	}
+
+	goos = oldgoos;
+	goarch = oldgoarch;
+	gochar = oldgochar;
+	xsetenv("GOARCH", goarch);
+	xsetenv("GOOS", goos);
+
+	// Build pkg/runtime for actual goos/goarch too.
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch))
+		install("pkg/runtime");
+
 	bfree(&b);
 }
 
diff --git a/src/cmd/dist/buildruntime.c b/src/cmd/dist/buildruntime.c
index dfecc2be0d6..03ebd345fd9 100644
--- a/src/cmd/dist/buildruntime.c
+++ b/src/cmd/dist/buildruntime.c
@@ -191,7 +191,7 @@ ok:
 	// Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -a proc.c
 	// to get acid [sic] output.
 	vreset(&argv);
-	vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+	vadd(&argv, bpathf(&b, "%s/%sc", tooldir, gochar));
 	vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
 	vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
 	vadd(&argv, bprintf(&b, "-I%s", workdir));
@@ -287,7 +287,7 @@ mkzruntimedefs(char *dir, char *file)
 	
 	// Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -q
 	// on each of the runtimedefs C files.
-	vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+	vadd(&argv, bpathf(&b, "%s/%sc", tooldir, gochar));
 	vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
 	vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
 	vadd(&argv, bprintf(&b, "-I%s", workdir));
diff --git a/src/cmd/dist/goc2c.c b/src/cmd/dist/goc2c.c
index 6829dedc78c..2443c30b10b 100644
--- a/src/cmd/dist/goc2c.c
+++ b/src/cmd/dist/goc2c.c
@@ -709,15 +709,23 @@ goc2c(char *goc, char *c)
 
 	// TODO: set gcc=1 when using gcc
 
-	if(!gcc && streq(goarch, "amd64")) {
-		type_table[Uintptr].size = 8;
-		type_table[String].size = 16;
-		type_table[Slice].size = 8+4+4;
-		type_table[Eface].size = 8+8;
-		structround = 8;
+	if(!gcc) {
+		if(streq(goarch, "amd64")) {
+			type_table[Uintptr].size = 8;
+			type_table[String].size = 16;
+			type_table[Slice].size = 8+4+4;
+			type_table[Eface].size = 8+8;
+			structround = 8;
+		} else {
+			type_table[Uintptr].size = 4;
+			type_table[String].size = 8;
+			type_table[Slice].size = 16;
+			type_table[Eface].size = 4+4;
+			structround = 4;
+		}
 	}
 
-	bprintf(&out, "// auto generated by go tool dist\n\n");
+	bprintf(&out, "// auto generated by go tool dist\n// goos=%s goarch=%s\n\n", goos, goarch);
 	input = bstr(&in);
 	output = &out;
 
diff --git a/src/cmd/dist/unix.c b/src/cmd/dist/unix.c
index 632ebbcdbad..5aedbed18d1 100644
--- a/src/cmd/dist/unix.c
+++ b/src/cmd/dist/unix.c
@@ -145,6 +145,7 @@ static struct {
 	int pid;
 	int mode;
 	char *cmd;
+	Buf *b;
 } bg[MAXBG];
 static int nbg;
 static int maxnbg = nelem(bg);
@@ -219,6 +220,7 @@ genrun(Buf *b, char *dir, int mode, Vec *argv, int wait)
 	bg[nbg].pid = pid;
 	bg[nbg].mode = mode;
 	bg[nbg].cmd = btake(&cmd);
+	bg[nbg].b = b;
 	nbg++;
 	
 	if(wait)
@@ -233,6 +235,7 @@ bgwait1(void)
 {
 	int i, pid, status, mode;
 	char *cmd;
+	Buf *b;
 
 	errno = 0;
 	while((pid = wait(&status)) < 0) {
@@ -248,9 +251,13 @@ ok:
 	cmd = bg[i].cmd;
 	mode = bg[i].mode;
 	bg[i].pid = 0;
+	b = bg[i].b;
+	bg[i].b = nil;
 	bg[i] = bg[--nbg];
 	
 	if(mode == CheckExit && (!WIFEXITED(status) || WEXITSTATUS(status) != 0)) {
+		if(b != nil)
+			xprintf("%s\n", bstr(b));
 		fatal("FAILED: %s", cmd);
 	}
 	xfree(cmd);
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index da046eedbc2..b8af30e370b 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -347,14 +347,21 @@ func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action
 		a.deps = append(a.deps, b.action(depMode, depMode, p1))
 	}
 
-	if len(p.CgoFiles) > 0 {
-		var stk importStack
-		p1 := loadPackage("cmd/cgo", &stk)
-		if p1.Error != nil {
-			fatalf("load cmd/cgo: %v", p1.Error)
+	// If we are not doing a cross-build, then record the binary we'll
+	// generate for cgo as a dependency of the build of any package
+	// using cgo, to make sure we do not overwrite the binary while
+	// a package is using it.  If this is a cross-build, then the cgo we
+	// are writing is not the cgo we need to use.
+	if b.goos == runtime.GOOS && b.goarch == runtime.GOARCH {
+		if len(p.CgoFiles) > 0 || p.Standard && p.ImportPath == "runtime/cgo" {
+			var stk importStack
+			p1 := loadPackage("cmd/cgo", &stk)
+			if p1.Error != nil {
+				fatalf("load cmd/cgo: %v", p1.Error)
+			}
+			a.cgo = b.action(depMode, depMode, p1)
+			a.deps = append(a.deps, a.cgo)
 		}
-		a.cgo = b.action(depMode, depMode, p1)
-		a.deps = append(a.deps, a.cgo)
 	}
 
 	if p.Standard {
@@ -567,7 +574,11 @@ func (b *builder) build(a *action) error {
 			sfiles = nil
 		}
 
-		outGo, outObj, err := b.cgo(a.p, a.cgo.target, obj, gccfiles)
+		cgoExe := tool("cgo")
+		if a.cgo != nil {
+			cgoExe = a.cgo.target
+		}
+		outGo, outObj, err := b.cgo(a.p, cgoExe, obj, gccfiles)
 		if err != nil {
 			return err
 		}
diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go
index e9fe845c56d..00c5d30b50d 100644
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@@ -295,13 +295,14 @@ func scanPackage(ctxt *build.Context, t *build.Tree, arg, importPath, dir string
 
 	if info.Package == "main" {
 		_, elem := filepath.Split(importPath)
-		if ctxt.GOOS != toolGOOS || ctxt.GOARCH != toolGOARCH {
-			// Install cross-compiled binaries to subdirectories of bin.
-			elem = ctxt.GOOS + "_" + ctxt.GOARCH + "/" + elem
-		}
+		full := ctxt.GOOS + "_" + ctxt.GOARCH + "/" + elem
 		if t.Goroot && isGoTool[p.ImportPath] {
-			p.target = filepath.Join(t.Path, "bin/tool", elem)
+			p.target = filepath.Join(t.Path, "pkg/tool", full)
 		} else {
+			if ctxt.GOOS != toolGOOS || ctxt.GOARCH != toolGOARCH {
+				// Install cross-compiled binaries to subdirectories of bin.
+				elem = full
+			}
 			p.target = filepath.Join(t.BinDir(), elem)
 		}
 		if ctxt.GOOS == "windows" {
diff --git a/src/cmd/go/tool.go b/src/cmd/go/tool.go
index 0ec5cf6a747..19b0d37dc00 100644
--- a/src/cmd/go/tool.go
+++ b/src/cmd/go/tool.go
@@ -31,7 +31,7 @@ var (
 	toolGOOS      = runtime.GOOS
 	toolGOARCH    = runtime.GOARCH
 	toolIsWindows = toolGOOS == "windows"
-	toolDir       = filepath.Join(build.Path[0].Path, "bin", "tool")
+	toolDir       = build.ToolDir
 )
 
 const toolWindowsExtension = ".exe"
@@ -97,6 +97,7 @@ func listTools() {
 		setExitStatus(2)
 		return
 	}
+
 	sort.Strings(names)
 	for _, name := range names {
 		// Unify presentation by going to lower case.
diff --git a/src/make.bash b/src/make.bash
index 81ceeb7298d..e30743b6831 100755
--- a/src/make.bash
+++ b/src/make.bash
@@ -61,24 +61,36 @@ mkdir -p ../bin/tool
 export GOROOT="$(cd .. && pwd)"
 GOROOT_FINAL="${GOROOT_FINAL:-$GOROOT}"
 DEFGOROOT='-DGOROOT_FINAL="'"$GOROOT_FINAL"'"'
-gcc -O2 -Wall -Werror -o ../bin/tool/dist -Icmd/dist "$DEFGOROOT" cmd/dist/*.c
+gcc -O2 -Wall -Werror -ggdb -o cmd/dist/dist -Icmd/dist "$DEFGOROOT" cmd/dist/*.c
+eval $(./cmd/dist/dist env)
 echo
 
 if [ "$1" = "--dist-tool" ]; then
 	# Stop after building dist tool.
+	mv cmd/dist/dist $GOTOOLDIR/dist
 	exit 0
 fi
 
-echo '# Building compilers and Go bootstrap tool.'
-../bin/tool/dist bootstrap -v # builds go_bootstrap
+echo "# Building compilers and Go bootstrap tool for host, $GOHOSTOS/$GOHOSTARCH."
+./cmd/dist/dist bootstrap -a -v # builds go_bootstrap
+# Delay move of dist tool to now, because bootstrap cleared tool directory.
+mv cmd/dist/dist $GOTOOLDIR/dist
+$GOTOOLDIR/go_bootstrap clean -i std
 echo
 
-echo '# Building packages and commands.'
-../bin/tool/go_bootstrap clean std
-../bin/tool/go_bootstrap install -a -v std
-rm -f ../bin/tool/go_bootstrap
+if [ "$GOHOSTARCH" != "$GOARCH" -o "$GOHOSTOS" != "$GOOS" ]; then
+	echo "# Building packages and commands for host, $GOHOSTOS/$GOHOSTARCH."
+	GOOS=$GOHOSTOS GOARCH=$GOHOSTARCH \
+		$GOTOOLDIR/go_bootstrap install -v std
+	echo
+fi
+
+echo "# Building packages and commands for $GOOS/$GOARCH."
+$GOTOOLDIR/go_bootstrap install -v std
 echo
 
+rm -f $GOTOOLDIR/go_bootstrap
+
 if [ "$1" != "--no-banner" ]; then
-	../bin/tool/dist banner
+	$GOTOOLDIR/dist banner
 fi
diff --git a/src/make.bat b/src/make.bat
index 010e418c015..6618bc4ed98 100644
--- a/src/make.bat
+++ b/src/make.bat
@@ -25,26 +25,48 @@ echo # Building C bootstrap tool.
 echo cmd/dist
 if not exist ..\bin\tool mkdir ..\bin\tool
 :: Windows has no glob expansion, so spell out cmd/dist/*.c.
-gcc -O2 -Wall -Werror -o ../bin/tool/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c
+gcc -O2 -Wall -Werror -o cmd/dist/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c
 if errorlevel 1 goto fail
+.\cmd\dist\dist env -wp >env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
 :: Echo with no arguments prints whether echo is turned on, so echo dot.
 echo .
 
 echo # Building compilers and Go bootstrap tool.
-..\bin\tool\dist bootstrap -v
+.\cmd\dist\dist bootstrap -a -v
+if errorlevel 1 goto fail
+:: Delay move of dist tool to now, because bootstrap cleared tool directory.
+move .\cmd\dist\dist.exe %GOTOOLDIR%\dist.exe
+%GOTOOLDIR%\go_bootstrap clean -i std
+echo .
+
+if not %GOHOSTARCH% == %GOARCH% goto localbuild
+if not %GOHOSTOS% == %GOOS% goto localbuild
+goto mainbuild
+
+:localbuild
+echo # Building tools for local system. %GOHOSTOS%/%GOHOSTARCH%
+set oldGOOS=%GOOS%
+set oldGOARCH=%GOARCH%
+set GOOS=%GOHOSTOS%
+set GOARCH=%GOHOSTARCH%
+%GOTOOLDIR%\go_bootstrap install -v std
+set GOOS=%oldGOOS%
+set GOARCH=%oldGOARCH%
 if errorlevel 1 goto fail
 echo .
 
+:mainbuild
 echo # Building packages and commands.
-..\bin\tool\go_bootstrap clean std
+%GOTOOLDIR%\go_bootstrap install -a -v std
 if errorlevel 1 goto fail
-..\bin\tool\go_bootstrap install -a -v std
-if errorlevel 1 goto fail
-del ..\bin\tool\go_bootstrap.exe
+del %GOTOOLDIR%\go_bootstrap.exe
 echo .
 
 if "x%1"=="x--no-banner" goto nobanner
-..\bin\tool\dist banner
+%GOTOOLDIR%\dist banner
 :nobanner
 
 goto end
diff --git a/src/pkg/exp/types/gcimporter_test.go b/src/pkg/exp/types/gcimporter_test.go
index 5411f3bccef..c229b50113d 100644
--- a/src/pkg/exp/types/gcimporter_test.go
+++ b/src/pkg/exp/types/gcimporter_test.go
@@ -6,7 +6,9 @@ package types
 
 import (
 	"go/ast"
+	"go/build"
 	"io/ioutil"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -31,7 +33,7 @@ func init() {
 		gcPath = gcName
 		return
 	}
-	gcPath = filepath.Join(runtime.GOROOT(), "/bin/tool/", gcName)
+	gcPath = filepath.Join(build.ToolDir, gcName)
 }
 
 func compile(t *testing.T, dirname, filename string) {
@@ -90,6 +92,13 @@ func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
 }
 
 func TestGcImport(t *testing.T) {
+	// On cross-compile builds, the path will not exist.
+	// Need to use GOHOSTOS, which is not available.
+	if _, err := os.Stat(gcPath); err != nil {
+		t.Logf("skipping test: %v", err)
+		return
+	}
+
 	compile(t, "testdata", "exports.go")
 
 	nimports := 0
diff --git a/src/pkg/go/build/path.go b/src/pkg/go/build/path.go
index 7e931faff19..e160ac3b280 100644
--- a/src/pkg/go/build/path.go
+++ b/src/pkg/go/build/path.go
@@ -12,6 +12,9 @@ import (
 	"runtime"
 )
 
+// ToolDir is the directory containing build tools.
+var ToolDir = filepath.Join(runtime.GOROOT(), "pkg/tool/"+runtime.GOOS+"_"+runtime.GOARCH)
+
 // Path is a validated list of Trees derived from $GOROOT and $GOPATH at init.
 var Path []*Tree
 
diff --git a/src/run.bash b/src/run.bash
index 8f282249fb8..d818751b2c6 100755
--- a/src/run.bash
+++ b/src/run.bash
@@ -5,7 +5,7 @@
 
 set -e
 
-eval $(../bin/tool/dist env -p)
+eval $(go tool dist env)
 
 unset CDPATH	# in case user has it set
 
diff --git a/test/fixedbugs/bug302.go b/test/fixedbugs/bug302.go
index b42db7f72be..1088b2f3c29 100644
--- a/test/fixedbugs/bug302.go
+++ b/test/fixedbugs/bug302.go
@@ -1,4 +1,4 @@
-// $G $D/bug302.dir/p.go && "$GOROOT"/bin/tool/pack grc pp.a p.$A && $G $D/bug302.dir/main.go
+// $G $D/bug302.dir/p.go && pack grc pp.a p.$A && $G $D/bug302.dir/main.go
 
 // Copyright 2010 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/test/run b/test/run
index 4b0481caa8b..7f4c350fa32 100755
--- a/test/run
+++ b/test/run
@@ -3,7 +3,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-eval $(../bin/tool/dist env)
+eval $(go tool dist env)
 export GOARCH GOOS GOROOT
 export E=
 
@@ -34,7 +34,7 @@ failed=0
 PATH=${GOBIN:-$GOROOT/bin}:`pwd`:/bin:/usr/bin:/usr/local/bin
 
 # TODO: We add the tool directory to the PATH to avoid thinking about a better way.
-PATH="$GOROOT/bin/tool":$PATH
+PATH="$GOTOOLDIR:$PATH"
 
 RUNFILE="/tmp/gorun-$$-$USER"
 TMP1FILE="/tmp/gotest1-$$-$USER"