diff --git a/src/cmd/go/internal/cfg/cfg.go b/src/cmd/go/internal/cfg/cfg.go
index b50074f0af..0d8e264eb7 100644
--- a/src/cmd/go/internal/cfg/cfg.go
+++ b/src/cmd/go/internal/cfg/cfg.go
@@ -131,7 +131,24 @@ func isGOROOT(path string) bool {
 
 // ExternalLinkingForced reports whether external linking is being
 // forced even for programs that do not use cgo.
-func ExternalLinkingForced() bool {
+func ExternalLinkingForced(inGoroot bool) bool {
+	// Some targets must use external linking even inside GOROOT.
+	switch BuildContext.GOOS {
+	case "android":
+		return true
+	case "darwin":
+		switch BuildContext.GOARCH {
+		case "arm", "arm64":
+			return true
+		}
+	}
+
+	// Otherwise we disable forcing of external linking for GOROOT binaries.
+	// This is primarily for cgo, so we will be able to relax this soon.
+	if inGoroot {
+		return false
+	}
+
 	if !BuildContext.CgoEnabled {
 		return false
 	}
@@ -151,5 +168,6 @@ func ExternalLinkingForced() bool {
 			linkmodeExternal = true
 		}
 	}
+
 	return BuildBuildmode == "c-shared" || BuildBuildmode == "plugin" || pieCgo || BuildLinkshared || linkmodeExternal
 }
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 63e58c6247..dace766aed 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -946,7 +946,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) {
 		importPaths = append(importPaths, "syscall")
 	}
 
-	if p.Name == "main" && !p.Goroot && cfg.ExternalLinkingForced() {
+	if p.Name == "main" && cfg.ExternalLinkingForced(p.Goroot) {
 		importPaths = append(importPaths, "runtime/cgo")
 	}
 
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index bdedd25651..c3810feb0d 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -815,16 +815,10 @@ func builderTest(b *work.Builder, p *load.Package) (buildAction, runAction, prin
 		},
 	}
 
-	// The generated main also imports testing, regexp, os, and maybe runtime/cgo.
+	// The generated main also imports testing, regexp, and os.
 	stk.Push("testmain")
-	forceCgo := false
-	if cfg.BuildContext.GOOS == "darwin" {
-		if cfg.BuildContext.GOARCH == "arm" || cfg.BuildContext.GOARCH == "arm64" {
-			forceCgo = true
-		}
-	}
 	deps := testMainDeps
-	if cfg.ExternalLinkingForced() || forceCgo {
+	if cfg.ExternalLinkingForced(pmain.Goroot) {
 		deps = str.StringList(deps, "runtime/cgo")
 	}
 	for _, dep := range deps {
@@ -889,8 +883,6 @@ func builderTest(b *work.Builder, p *load.Package) (buildAction, runAction, prin
 		recompileForTest(pmain, p, ptest)
 	}
 
-	t.NeedCgo = forceCgo
-
 	for _, cp := range pmain.Internal.Imports {
 		if len(cp.Internal.CoverVars) > 0 {
 			t.Cover = append(t.Cover, coverInfo{cp, cp.Internal.CoverVars})
@@ -1319,7 +1311,6 @@ type testFuncs struct {
 	NeedTest    bool
 	ImportXtest bool
 	NeedXtest   bool
-	NeedCgo     bool
 	Cover       []coverInfo
 }
 
@@ -1448,10 +1439,6 @@ import (
 {{range $i, $p := .Cover}}
 	_cover{{$i}} {{$p.Package.ImportPath | printf "%q"}}
 {{end}}
-
-{{if .NeedCgo}}
-	_ "runtime/cgo"
-{{end}}
 )
 
 var tests = []testing.InternalTest{
diff --git a/src/runtime/cgo/gcc_signal2_darwin_armx.c b/src/runtime/cgo/gcc_signal2_darwin_armx.c
new file mode 100644
index 0000000000..6da623b3b1
--- /dev/null
+++ b/src/runtime/cgo/gcc_signal2_darwin_armx.c
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build lldb
+// +build darwin
+// +build arm arm64
+
+// Used by gcc_signal_darwin_armx.c when doing the test build during cgo.
+// We hope that for real binaries the definition provided by Go will take precedence
+// and the linker will drop this .o file altogether, which is why this definition
+// is all by itself in its own file.
+void xx_cgo_panicmem(void) {}
diff --git a/src/runtime/cgo/gcc_signal_darwin_armx.c b/src/runtime/cgo/gcc_signal_darwin_armx.c
index a2d520bce8..3ab1d8b0d6 100644
--- a/src/runtime/cgo/gcc_signal_darwin_armx.c
+++ b/src/runtime/cgo/gcc_signal_darwin_armx.c
@@ -39,7 +39,8 @@
 #include "libcgo.h"
 #include "libcgo_unix.h"
 
-uintptr_t x_cgo_panicmem;
+void xx_cgo_panicmem(void);
+uintptr_t x_cgo_panicmem = (uintptr_t)xx_cgo_panicmem;
 
 static pthread_mutex_t mach_exception_handler_port_set_mu;
 static mach_port_t mach_exception_handler_port_set = MACH_PORT_NULL;
diff --git a/src/runtime/cgo/gcc_signal_darwin_lldb.c b/src/runtime/cgo/gcc_signal_darwin_lldb.c
index 12cc388400..54d91f6390 100644
--- a/src/runtime/cgo/gcc_signal_darwin_lldb.c
+++ b/src/runtime/cgo/gcc_signal_darwin_lldb.c
@@ -8,7 +8,5 @@
 
 #include <stdint.h>
 
-uintptr_t x_cgo_panicmem;
-
 void darwin_arm_init_thread_exception_port() {}
 void darwin_arm_init_mach_exception_handler() {}
diff --git a/src/runtime/cgo/signal_darwin_armx.go b/src/runtime/cgo/signal_darwin_armx.go
index 9f6741eb08..e1d9e54c46 100644
--- a/src/runtime/cgo/signal_darwin_armx.go
+++ b/src/runtime/cgo/signal_darwin_armx.go
@@ -7,29 +7,7 @@
 
 package cgo
 
-import "unsafe"
-
-//go:cgo_import_static x_cgo_panicmem
-//go:linkname x_cgo_panicmem x_cgo_panicmem
-var x_cgo_panicmem uintptr
-
-// use a pointer to avoid relocation of external symbol in __TEXT
-// make linker happy
-var _cgo_panicmem = &x_cgo_panicmem
-
-// TODO(crawshaw): move this into x_cgo_init, it will not run until
-// runtime has finished loading, which may be after its use.
-func init() {
-	*_cgo_panicmem = funcPC(panicmem)
-}
-
-func funcPC(f interface{}) uintptr {
-	var ptrSize = unsafe.Sizeof(uintptr(0))
-	return **(**uintptr)(add(unsafe.Pointer(&f), ptrSize))
-}
-
-func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
-	return unsafe.Pointer(uintptr(p) + x)
-}
+import _ "unsafe"
 
+//go:cgo_export_static panicmem xx_cgo_panicmem
 func panicmem()