NativeClient complains about __memset_chk being undefined on OSX.

Work around this. There might be a better fix, but at least the
test suite compiles with the newlib.

test/quirks/quirks.h

@@ -4,12 +4,32 @@
 /* C++Builder defines a "random" macro */
 #undef random
 
+#ifdef __native_client__
+# define memset(dst, c, n) xmemset(dst, c, n)
+static void *
+xmemset(void *dst, int c, size_t n)
+{
+    unsigned char      *dst_ = (unsigned char *) dst;
+    const unsigned char c_ = (unsigned char) c;
+    size_t              i;
+
+    for (i = 0; i < n; i++) {
+        dst_[i] = c_;
+    }
+    return dst;
+}
+#endif
+
 #ifdef __EMSCRIPTEN__
 # define strcmp(s1, s2) xstrcmp(s1, s2)
 
-int
+static int
 strcmp(const char *s1, const char *s2) {
-    while (*s1 == *s2++) { if (*s1++ == 0) return 0; }
+    while (*s1 == *s2++) {
+        if (*s1++ == 0) {
+            return 0;
+        }
+    }
     return *(unsigned char *) s1 - *(unsigned char *) --s2;
 }
 #endif