Include namespace.h in GCDAProfiling.c (compiler_rt)

The NetBSD Standard C Library uses internally some of its functions with
a mangled symbol name, usually "_symbol". The internal functions shall not
use the global (public) symbols.

This change eliminates usage of the global name of the following symbols:
  - fdopen -> _fdopen
  - mmap -> _mmap
  - strdup -> _strdup

Sponsored by <The NetBSD Foundation>

sys/external/bsd/compiler_rt/dist/lib/profile/GCDAProfiling.c

@@ -20,6 +20,10 @@
 |*
 \*===----------------------------------------------------------------------===*/
 
+#ifdef _LIBC
+#include "namespace.h"
+#endif
+
 #include "InstrProfilingUtil.h"
 
 #include <errno.h>