linux-user: Fix compilation with clang 3.4
Clang version 3.4.2 does not know the -Wpragmas option yet and bails
out with an error when we try to disable it in linux-user/qemu.h.
Fortunately, clang has a __has_warning() macro which allows us to add
an explicit check for the option that we want to ignore. With that we
can check for the availability of "-Waddress-of-packed-member" properly
and do not need the "-Wpragmas" at all here.
Fixes: 850d5e330a9c68cc998cecc02caf8a3c8d1ee8a3
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 069df8f..ef400cb 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -474,17 +474,13 @@
* functions than host-endian unaligned load/store plus tswapN.
* - The pragmas are necessary only to silence a clang false-positive
* warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
- * - We have to disable -Wpragmas warnings to avoid a complaint about
- * an unknown warning type from older compilers that don't know about
- * -Waddress-of-packed-member.
* - gcc has bugs in its _Pragma() support in some versions, eg
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
* include the warning-suppression pragmas for clang
*/
-#ifdef __clang__
+#if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
#define PRAGMA_DISABLE_PACKED_WARNING \
_Pragma("GCC diagnostic push"); \
- _Pragma("GCC diagnostic ignored \"-Wpragmas\""); \
_Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
#define PRAGMA_REENABLE_PACKED_WARNING \