Clang 3.5 has -Wreturn-type-c-linkage

Change-Id: I9d4b8aef3877f46c537937f7cb04c7654f057fa2
Reviewed-on: https://gerrit.libreoffice.org/46789Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

include/osl/diagnose.hxx

@@ -65,9 +65,6 @@ SAL_DLLPUBLIC void SAL_CALL osl_detail_ObjectRegistry_revokeObject(
 // that would break binary compatibility.
 #ifdef __clang__
 #pragma clang diagnostic push
-// Guard against slightly older clang versions that don't have
-// -Wreturn-type-c-linkage...
-#pragma clang diagnostic ignored "-Wunknown-pragmas"
 #pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
 #endif
 

sal/osl/all/debugbase.cxx

@@ -68,9 +68,6 @@ extern "C" {
 // that would break binary compatibility.
 #ifdef __clang__
 #pragma clang diagnostic push
-// Guard against slightly older clang versions that don't have
-// -Wreturn-type-c-linkage...
-#pragma clang diagnostic ignored "-Wunknown-pragmas"
 #pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
 #endif