dist: add clang specific -Wno options

Clang 3.1 has more warnings enabled by default than GCC.
Combined with -Werror, they cause the build to fail
unnecessarily.  if the name of our compiler ends in "clang",
add the necessary extra -Wno options.  Ideally we would add
these flags unconditionally, as GCC is supposed to ignore
unknown -Wno flags, but apple's llvm-gcc doesn't.

Fixes #2878.

R=rsc, dave
CC=golang-dev
https://golang.org/cl/5673055

diff --git a/src/cmd/dist/build.c b/src/cmd/dist/build.c
index 9d168b364fbdab8f35112c4b5e808feb3bce47a2..f31c83ea7ad9fec4342ff49195ef146ccc004b3e 100644 (file)
--- a/src/cmd/dist/build.c
+++ b/src/cmd/dist/build.c
@@ -582,8 +582,12 @@ install(char *dir)
                splitfields(&gccargs, bstr(&b));
                for(i=0; i<nelem(proto_gccargs); i++)
                        vadd(&gccargs, proto_gccargs[i]);
+               if(xstrstr(gccargs.p[0], "clang") != nil) {
+                       vadd(&gccargs, "-Wno-dangling-else");
+                       vadd(&gccargs, "-Wno-unused-value");
+               }
        }
-       
+
        islib = hasprefix(dir, "lib") || streq(dir, "cmd/cc") || streq(dir, "cmd/gc");
        ispkg = hasprefix(dir, "pkg");
        isgo = ispkg || streq(dir, "cmd/go") || streq(dir, "cmd/cgo");