cmd/asm: add -e flag (no limit on errors) to match compiler

Change-Id: I5b749c575e0ec78fb3c50d056899bd1fe5d91853
Reviewed-on: https://go-review.googlesource.com/18847
Reviewed-by: Rob Pike <r@golang.org>

src/cmd/asm/internal/asm/parse.go

@@ -16,6 +16,7 @@ import (
 	"unicode/utf8"
 
 	"cmd/asm/internal/arch"
+	"cmd/asm/internal/flags"
 	"cmd/asm/internal/lex"
 	"cmd/internal/obj"
 )
@@ -78,7 +79,7 @@ func (p *Parser) errorf(format string, args ...interface{}) {
 	}
 	fmt.Fprintf(p.errorWriter, format, args...)
 	p.errorCount++
-	if p.errorCount > 10 {
+	if p.errorCount > 10 && !*flags.AllErrors {
 		log.Fatal("too many errors")
 	}
 }

src/cmd/asm/internal/flags/flags.go

@@ -20,6 +20,7 @@ var (
 	TrimPath   = flag.String("trimpath", "", "remove prefix from recorded source file paths")
 	Shared     = flag.Bool("shared", false, "generate code that can be linked into a shared library")
 	Dynlink    = flag.Bool("dynlink", false, "support references to Go symbols defined in other shared libraries")
+	AllErrors = flag.Bool("e", false, "no limit on number of errors reported")
 )
 
 var (