mesa: Fix Android build by #ifdef'ing out locale support

Bionic does not support locales. This commit #ifdef's out the locale usage
in _mesa_strtof().

Signed-off-by: Chad Versace <chad@chad-versace.us>

src/mesa/main/imports.c

@@ -753,7 +753,8 @@ _mesa_strdup( const char *s )
 float
 _mesa_strtof( const char *s, char **end )
 {
-#if defined(_GNU_SOURCE) && !defined(__CYGWIN__) && !defined(__FreeBSD__)
+#if defined(_GNU_SOURCE) && !defined(__CYGWIN__) && !defined(__FreeBSD__) && \
+    !defined(ANDROID)
    static locale_t loc = NULL;
    if (!loc) {
       loc = newlocale(LC_CTYPE_MASK, "C", NULL);