Bug 727145 - Pass -Wno-return-type-c-linkage to clang. r=glandium.

aclocal.m4

@@ -17,6 +17,7 @@ builtin(include, build/autoconf/acwinpaths.m4)dnl
 builtin(include, build/autoconf/lto.m4)dnl
 builtin(include, build/autoconf/gcc-pr49911.m4)dnl
 builtin(include, build/autoconf/frameptr.m4)dnl
+builtin(include, build/autoconf/compiler-opts.m4)dnl
 
 MOZ_PROG_CHECKMSYS()
 

build/autoconf/compiler-opts.m4

@@ -0,0 +1,13 @@
+dnl Add compiler specific options
+
+AC_DEFUN([MOZ_COMPILER_OPTS],
+[
+if test "$CLANG_CXX"; then
+    ## We disable return-type-c-linkage because jsval is defined as a C++ type but is
+    ## returned by C functions. This is possible because we use knowledge about the ABI
+    ## to typedef it to a C type with the same layout when the headers are included
+    ## from C.
+    _WARNINGS_CXXFLAGS="${_WARNINGS_CXXFLAGS} -Wno-return-type-c-linkage"
+fi
+])
+

configure.in

@@ -3343,6 +3343,7 @@ AC_SUBST(WRAP_SYSTEM_INCLUDES)
 AC_SUBST(VISIBILITY_FLAGS)
 
 MOZ_GCC_PR49911
+MOZ_COMPILER_OPTS
 
 dnl Check for __force_align_arg_pointer__ for SSE2 on gcc
 dnl ========================================================

js/src/aclocal.m4

@@ -14,5 +14,6 @@ builtin(include, build/autoconf/acwinpaths.m4)dnl
 builtin(include, build/autoconf/lto.m4)dnl
 builtin(include, build/autoconf/gcc-pr49911.m4)dnl
 builtin(include, build/autoconf/frameptr.m4)dnl
+builtin(include, build/autoconf/compiler-opts.m4)dnl
 
 MOZ_PROG_CHECKMSYS()

js/src/build/autoconf/compiler-opts.m4

@@ -0,0 +1,13 @@
+dnl Add compiler specific options
+
+AC_DEFUN([MOZ_COMPILER_OPTS],
+[
+if test "$CLANG_CXX"; then
+    ## We disable return-type-c-linkage because jsval is defined as a C++ type but is
+    ## returned by C functions. This is possible because we use knowledge about the ABI
+    ## to typedef it to a C type with the same layout when the headers are included
+    ## from C.
+    _WARNINGS_CXXFLAGS="${_WARNINGS_CXXFLAGS} -Wno-return-type-c-linkage"
+fi
+])
+

js/src/configure.in

@@ -3133,6 +3133,7 @@ AC_SUBST(WRAP_SYSTEM_INCLUDES)
 AC_SUBST(VISIBILITY_FLAGS)
 
 MOZ_GCC_PR49911
+MOZ_COMPILER_OPTS
 
 dnl Check for __force_align_arg_pointer__ for SSE2 on gcc
 dnl ========================================================