Wrap stdint.h include in #ifdef.

openbsd-compat/recallocarray.c

@@ -22,7 +22,9 @@
 
 #include <errno.h>
 #include <stdlib.h>
+#ifdef HAVE_STDINT_H
 #include <stdint.h>
+#endif
 #include <string.h>
 #include <unistd.h>