util: Add strings.h include on unices

Fixes -Wimplicit-function-declaration for ffs with GCC.  Spotted/tested
by Kai Wasserbäch.

diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index f908341f6242e5dbbf2edc8edba365ef45ba874d..404bd21e1c595532533410d8fa52221d71633f7e 100644 (file)
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -51,6 +51,10 @@ extern "C" {
 #include <math.h>
 #include <stdarg.h>
 
+#ifdef PIPE_OS_UNIX
+#include <strings.h> /* for ffs */
+#endif
+
 
 #ifndef M_SQRT2
 #define M_SQRT2 1.41421356237309504880