Add platform specific version tags.
Some functions were added at different times on different platforms.
This should hopefully get most of them.
Bug: http://b/28178111
Change-Id: I85fdf92779a2f3277e9b537c6bfc7216790c607a
diff --git a/libc/include/strings.h b/libc/include/strings.h
index 1200e77..ca9f658 100644
--- a/libc/include/strings.h
+++ b/libc/include/strings.h
@@ -54,7 +54,11 @@
#define bzero(b, len) (void)(__builtin_memset((b), '\0', (len)))
#endif
+#if defined(__i386__)
+int ffs(int) __INTRODUCED_IN(21);
+#else
int ffs(int);
+#endif
__END_DECLS