mesa: Try to unbreak the MSVC build.

PATH_MAX is apparently not a thing on Windows.  Borrow the hack from
pipe_loader.c to try and make this work.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/main/arbprogram.c

@@ -41,6 +41,10 @@
 #include "program/program.h"
 #include "program/prog_print.h"
 
+#ifdef _MSC_VER
+#include <stdlib.h>
+#define PATH_MAX _MAX_PATH
+#endif
 
 /**
  * Bind a program (make it current)

src/mesa/main/shaderapi.c

@@ -60,6 +60,10 @@
 #include "util/hash_table.h"
 #include "util/mesa-sha1.h"
 
+#ifdef _MSC_VER
+#include <stdlib.h>
+#define PATH_MAX _MAX_PATH
+#endif
 
 /**
  * Return mask of GLSL_x flags by examining the MESA_GLSL env var.