From: Mikio Hara <mikioh.mikioh@gmail.com>
Date: Thu, 22 Dec 2011 14:18:34 +0000 (+0900)
Subject: cmd/gc: make sure use of pthread for gcc-4.5 and beyond
X-Git-Tag: weekly.2011-12-22~32
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e636f6f51c073b7539b01fc2fcc7c17e25e29294;p=gostls13.git

cmd/gc: make sure use of pthread for gcc-4.5 and beyond

R=golang-dev, rsc, n13m3y3r, rogpeppe
CC=golang-dev
https://golang.org/cl/5501060
---

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index b79a522dc9..62c8d90d30 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -912,6 +912,16 @@ func (b *builder) gccCmd(objdir string, flags []string, args ...string) []string
 	case "6":
 		a = append(a, "-m64")
 	}
+	// gcc-4.5 and beyond require explicit "-pthread" flag
+	// for multithreading with pthread library.
+	if build.DefaultContext.CgoEnabled {
+		switch b.goos {
+		case "windows":
+			a = append(a, "-mthread")
+		default:
+			a = append(a, "-pthread")
+		}
+	}
 	a = append(a, flags...)
 	return append(a, args...)
 }