diff --git a/zconf.h b/zconf.h
index 0154955..5338de6 100644
--- a/zconf.h
+++ b/zconf.h
@@ -399,17 +399,17 @@ typedef uLong FAR uLongf;
 #  endif
 #endif
 
-/* accommodate both "#define _LARGEFILE64_SOURCE" and
+/* a little trick to accommodate both "#define _LARGEFILE64_SOURCE" and
  * "#define _LARGEFILE64_SOURCE 1" as requesting 64-bit operations, (even
- * though the former does not conform to the LFS document), but consider
+ * though the former does not conform to the LFS document), but considering
  * both "#undef _LARGEFILE64_SOURCE" and "#define _LARGEFILE64_SOURCE 0" as
  * equivalently requesting no 64-bit operations
  */
-#if defined(LARGEFILE64_SOURCE) && _LARGEFILE64_SOURCE == 0
+#if defined(LARGEFILE64_SOURCE) && -_LARGEFILE64_SOURCE - -1 == 1
 #  undef _LARGEFILE64_SOURCE
 #endif
 
-#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE == 1
+#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
 
@@ -417,7 +417,7 @@ typedef uLong FAR uLongf;
 #  define Z_LARGE64
 #endif
 
-#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64 && defined(Z_LFS64)
+#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS-0 == 64 && defined(Z_LFS64)
 #  define Z_WANT64
 #endif
 
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index af4e92e..c08d177 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -401,17 +401,17 @@ typedef uLong FAR uLongf;
 #  endif
 #endif
 
-/* accommodate both "#define _LARGEFILE64_SOURCE" and
+/* a little trick to accommodate both "#define _LARGEFILE64_SOURCE" and
  * "#define _LARGEFILE64_SOURCE 1" as requesting 64-bit operations, (even
- * though the former does not conform to the LFS document), but consider
+ * though the former does not conform to the LFS document), but considering
  * both "#undef _LARGEFILE64_SOURCE" and "#define _LARGEFILE64_SOURCE 0" as
  * equivalently requesting no 64-bit operations
  */
-#if defined(LARGEFILE64_SOURCE) && _LARGEFILE64_SOURCE == 0
+#if defined(LARGEFILE64_SOURCE) && -_LARGEFILE64_SOURCE - -1 == 1
 #  undef _LARGEFILE64_SOURCE
 #endif
 
-#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE == 1
+#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
 
@@ -419,7 +419,7 @@ typedef uLong FAR uLongf;
 #  define Z_LARGE64
 #endif
 
-#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64 && defined(Z_LFS64)
+#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS-0 == 64 && defined(Z_LFS64)
 #  define Z_WANT64
 #endif
 
diff --git a/zconf.h.in b/zconf.h.in
index 0154955..5338de6 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -399,17 +399,17 @@ typedef uLong FAR uLongf;
 #  endif
 #endif
 
-/* accommodate both "#define _LARGEFILE64_SOURCE" and
+/* a little trick to accommodate both "#define _LARGEFILE64_SOURCE" and
  * "#define _LARGEFILE64_SOURCE 1" as requesting 64-bit operations, (even
- * though the former does not conform to the LFS document), but consider
+ * though the former does not conform to the LFS document), but considering
  * both "#undef _LARGEFILE64_SOURCE" and "#define _LARGEFILE64_SOURCE 0" as
  * equivalently requesting no 64-bit operations
  */
-#if defined(LARGEFILE64_SOURCE) && _LARGEFILE64_SOURCE == 0
+#if defined(LARGEFILE64_SOURCE) && -_LARGEFILE64_SOURCE - -1 == 1
 #  undef _LARGEFILE64_SOURCE
 #endif
 
-#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE == 1
+#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
 
@@ -417,7 +417,7 @@ typedef uLong FAR uLongf;
 #  define Z_LARGE64
 #endif
 
-#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64 && defined(Z_LFS64)
+#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS-0 == 64 && defined(Z_LFS64)
 #  define Z_WANT64
 #endif