diff --git a/zconf.h b/zconf.h
index 80de2ce..7a9d8f2 100644
--- a/zconf.h
+++ b/zconf.h
@@ -393,11 +393,11 @@ typedef uLong FAR uLongf;
 
 #if !defined(Z_U4) && !defined(Z_SOLO) && defined(STDC)
 #  include <limits.h>
-#  if (UINT_MAX == 4294967295)
+#  if (UINT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned
-#  elif (ULONG_MAX == 4294967295)
+#  elif (ULONG_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned long
-#  elif (USHRT_MAX == 4294967295)
+#  elif (USHRT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned short
 #  endif
 #endif
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index a02281a..10e445f 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -395,11 +395,11 @@ typedef uLong FAR uLongf;
 
 #if !defined(Z_U4) && !defined(Z_SOLO) && defined(STDC)
 #  include <limits.h>
-#  if (UINT_MAX == 4294967295)
+#  if (UINT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned
-#  elif (ULONG_MAX == 4294967295)
+#  elif (ULONG_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned long
-#  elif (USHRT_MAX == 4294967295)
+#  elif (USHRT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned short
 #  endif
 #endif
diff --git a/zconf.h.in b/zconf.h.in
index 80de2ce..7a9d8f2 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -393,11 +393,11 @@ typedef uLong FAR uLongf;
 
 #if !defined(Z_U4) && !defined(Z_SOLO) && defined(STDC)
 #  include <limits.h>
-#  if (UINT_MAX == 4294967295)
+#  if (UINT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned
-#  elif (ULONG_MAX == 4294967295)
+#  elif (ULONG_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned long
-#  elif (USHRT_MAX == 4294967295)
+#  elif (USHRT_MAX == 0xffffffffUL)
 #    define Z_U4 unsigned short
 #  endif
 #endif