@@ -568,10 +568,24 @@
 ], [
 	AC_MSG_RESULT(no)
 	AC_DEFINE(SSIZE_MAX, [((ssize_t)(SIZE_MAX / 2))],
 		[Maximum value for ssize_t])
 ])
+AC_MSG_CHECKING(for UINTPTR_MAX)
+AC_EGREP_CPP(yes, [
+	#include <stdint.h>
+	#include <limits.h>
+
+	#ifdef UINTPTR_MAX
+	yes
+	#endif
+], [
+	AC_MSG_RESULT(yes)
+], [
+	AC_MSG_RESULT(no)
+	AC_DEFINE(UINTPTR_MAX, [(~(uintptr_t)0)], [Maximum value for uintptr_t])
+])
 
 AC_CHECK_HEADER(sys/types.h,
 	[AC_DEFINE(OF_HAVE_SYS_TYPES_H, 1, [Whether we have <sys/types.h>])])
 
 AC_CHECK_TYPE(max_align_t,