Fixed missing alloc macro on mingw32, I think.

CHANGELOG.txt

@@ -2,6 +2,7 @@
  * CHANGELOG.
  */
 
+07122007 - Maybe fixed compile on mingw32.
 07112007 - Fixed crash on zero-byte read/write (thanks, Ensiform!).
 05272007 - FIXME removal: Replaced a strncpy() with a memcpy().
 05112007 - Minor documentation correction.

physfs_internal.h

@@ -29,6 +29,10 @@
 #include <malloc.h>
 #endif
 
+#ifdef __MINGW32__
+#include <alloca.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif