From 84e7bc0dd39bab24b696dde4d714641fa738f945 Mon Sep 17 00:00:00 2001
From: Alan Donovan <alan@alandonovan.net>
Date: Tue, 29 Mar 2016 14:32:15 -0400
Subject: [PATCH] go/loader: don't pass ldflags to cgo

Although these flags are harmless on linux, they
cause clang on darwin to issue an error about
unused flags (-lpthread).  We only care about compilation
so we don't need them.

Change-Id: I0fc756e2f4d7a829d43b5aa912c4e4b24a802a1c
Reviewed-on: https://go-review.googlesource.com/21283
Reviewed-by: Robert Griesemer <gri@golang.org>
---
 go/loader/cgo.go           |  7 +++----
 go/loader/cgo_pkgconfig.go | 18 ++++++------------
 2 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/go/loader/cgo.go b/go/loader/cgo.go
index c925ace405..245b914914 100644
--- a/go/loader/cgo.go
+++ b/go/loader/cgo.go
@@ -115,16 +115,15 @@ var cgoRe = regexp.MustCompile(`[/\\:]`)
 // Objective C, CGOPKGPATH, CGO_FLAGS.
 //
 func runCgo(bp *build.Package, pkgdir, tmpdir string) (files, displayFiles []string, err error) {
-	cgoCPPFLAGS, _, _, cgoLDFLAGS := cflags(bp, true)
+	cgoCPPFLAGS, _, _, _ := cflags(bp, true)
 	_, cgoexeCFLAGS, _, _ := cflags(bp, false)
 
 	if len(bp.CgoPkgConfig) > 0 {
-		pcCFLAGS, pcLDFLAGS, err := pkgConfigFlags(bp)
+		pcCFLAGS, err := pkgConfigFlags(bp)
 		if err != nil {
 			return nil, nil, err
 		}
 		cgoCPPFLAGS = append(cgoCPPFLAGS, pcCFLAGS...)
-		cgoLDFLAGS = append(cgoLDFLAGS, pcLDFLAGS...)
 	}
 
 	// Allows including _cgo_export.h from .[ch] files in the package.
@@ -150,7 +149,7 @@ func runCgo(bp *build.Package, pkgdir, tmpdir string) (files, displayFiles []str
 
 	args := stringList(
 		"go", "tool", "cgo", "-objdir", tmpdir, cgoflags, "--",
-		cgoCPPFLAGS, cgoLDFLAGS, cgoexeCFLAGS, bp.CgoFiles,
+		cgoCPPFLAGS, cgoexeCFLAGS, bp.CgoFiles,
 	)
 	if false {
 		log.Printf("Running cgo for package %q: %s (dir=%s)", bp.ImportPath, args, pkgdir)
diff --git a/go/loader/cgo_pkgconfig.go b/go/loader/cgo_pkgconfig.go
index 91ab2ccf9e..de57422df2 100644
--- a/go/loader/cgo_pkgconfig.go
+++ b/go/loader/cgo_pkgconfig.go
@@ -29,17 +29,11 @@ func pkgConfig(mode string, pkgs []string) (flags []string, err error) {
 	return
 }
 
-// pkgConfigFlags calls pkg-config if needed and returns the cflags/ldflags needed to build the package.
-func pkgConfigFlags(p *build.Package) (cflags, ldflags []string, err error) {
-	if pkgs := p.CgoPkgConfig; len(pkgs) > 0 {
-		cflags, err = pkgConfig("--cflags", pkgs)
-		if err != nil {
-			return nil, nil, err
-		}
-		ldflags, err = pkgConfig("--libs", pkgs)
-		if err != nil {
-			return nil, nil, err
-		}
+// pkgConfigFlags calls pkg-config if needed and returns the cflags
+// needed to build the package.
+func pkgConfigFlags(p *build.Package) (cflags []string, err error) {
+	if len(p.CgoPkgConfig) == 0 {
+		return nil, nil
 	}
-	return
+	return pkgConfig("--cflags", p.CgoPkgConfig)
 }