Workarounds in cdefs-compat for clang.

include/cdefs-compat.h

@@ -49,6 +49,10 @@
 	__asm__(".asciz \"msg\"");	\
 	__asm__(".previous")
 #endif	/* __STDC__ */
+#elif defined(__clang__) /* CLANG */
+#define __weak_reference(sym,alias)    \
+       __asm__(".weak_reference alias");\
+       __asm__(".set alias, sym")
 #else	/* !__ELF__ */
 #ifdef __STDC__
 #define __weak_reference(sym,alias)	\