osdep: fix HAVE_BROKEN_SIZE_MAX case

While config-host.mak entries are expanded to "1" for compatibility with
create-config.sh, tests done directly in meson.build expand to the empty
string and cannot be placed to the right of the && operator.  Adjust
osdep.h after commit e46bd55d9c ("configure: convert HAVE_BROKEN_SIZE_MAX
to meson", 2021-07-06) changed the way HAVE_BROKEN_SIZE_MAX is defined.

Reported-by: Frederic Bezies <fredbezies@gmail.com>
Fixes: e46bd55d9c ("configure: convert HAVE_BROKEN_SIZE_MAX to meson", 2021-07-06)
Resolves: #463
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/qemu/osdep.h

@@ -256,7 +256,7 @@ extern "C" {
 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
  * the wrong type. Our replacement isn't usable in preprocessor
  * expressions, but it is sufficient for our needs. */
-#if defined(HAVE_BROKEN_SIZE_MAX) && HAVE_BROKEN_SIZE_MAX
+#ifdef HAVE_BROKEN_SIZE_MAX
 #undef SIZE_MAX
 #define SIZE_MAX ((size_t)-1)
 #endif