configure: Don't use __int128_t for clang versions before 3.2

Those versions don't fully support __int128_t.

Cc: qemu-stable@nongnu.org
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

configure

@@ -3822,6 +3822,11 @@ fi
 
 int128=no
 cat > $TMPC << EOF
+#if defined(__clang_major__) && defined(__clang_minor__)
+# if ((__clang_major__ < 3) || (__clang_major__ == 3) && (__clang_minor__ < 2))
+#  error __int128_t does not work in CLANG before 3.2
+# endif
+#endif
 __int128_t a;
 __uint128_t b;
 int main (void) {