misc] move formatting functions into their own source

* also add missing #pragma once in msapi_utf8.h

stdio.c

@@ -16,6 +16,10 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#ifdef _CRTDBG_MAP_ALLOC
+#include <stdlib.h>
+#include <crtdbg.h>
+#endif
 
 #include <windows.h>
 #include <stdio.h>