diff --git a/zconf.h b/zconf.h
index 5338de6..af35c38 100644
--- a/zconf.h
+++ b/zconf.h
@@ -409,6 +409,21 @@ typedef uLong FAR uLongf;
 #  undef _LARGEFILE64_SOURCE
 #endif
 
+#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
+#  define Z_HAVE_UNISTD_H
+#endif
+#ifndef Z_SOLO
+#  if defined(Z_HAVE_UNISTD_H) || defined(LARGEFILE64_SOURCE)
+#    include <unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    ifdef VMS
+#      include <unixio.h>       /* for off_t */
+#    endif
+#    ifndef z_off_t
+#      define z_off_t off_t
+#    endif
+#  endif
+#endif
+
 #if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
@@ -421,19 +436,6 @@ typedef uLong FAR uLongf;
 #  define Z_WANT64
 #endif
 
-#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
-#  define Z_HAVE_UNISTD_H
-#endif
-#if (defined(Z_HAVE_UNISTD_H) || defined(Z_LARGE64)) && !defined(Z_SOLO)
-#  include <unistd.h>       /* for SEEK_* and off_t */
-#  ifdef VMS
-#    include <unixio.h>     /* for off_t */
-#  endif
-#  ifndef z_off_t
-#    define z_off_t off_t
-#  endif
-#endif
-
 #if !defined(SEEK_SET) && !defined(Z_SOLO)
 #  define SEEK_SET        0       /* Seek from beginning of file.  */
 #  define SEEK_CUR        1       /* Seek from current position.  */
@@ -444,7 +446,7 @@ typedef uLong FAR uLongf;
 #  define z_off_t long
 #endif
 
-#if !defined(_WIN32) && (defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0)
+#if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
 #  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index c08d177..81a7b7a 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -411,6 +411,21 @@ typedef uLong FAR uLongf;
 #  undef _LARGEFILE64_SOURCE
 #endif
 
+#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
+#  define Z_HAVE_UNISTD_H
+#endif
+#ifndef Z_SOLO
+#  if defined(Z_HAVE_UNISTD_H) || defined(LARGEFILE64_SOURCE)
+#    include <unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    ifdef VMS
+#      include <unixio.h>       /* for off_t */
+#    endif
+#    ifndef z_off_t
+#      define z_off_t off_t
+#    endif
+#  endif
+#endif
+
 #if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
@@ -423,19 +438,6 @@ typedef uLong FAR uLongf;
 #  define Z_WANT64
 #endif
 
-#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
-#  define Z_HAVE_UNISTD_H
-#endif
-#if (defined(Z_HAVE_UNISTD_H) || defined(Z_LARGE64)) && !defined(Z_SOLO)
-#  include <unistd.h>       /* for SEEK_* and off_t */
-#  ifdef VMS
-#    include <unixio.h>     /* for off_t */
-#  endif
-#  ifndef z_off_t
-#    define z_off_t off_t
-#  endif
-#endif
-
 #if !defined(SEEK_SET) && !defined(Z_SOLO)
 #  define SEEK_SET        0       /* Seek from beginning of file.  */
 #  define SEEK_CUR        1       /* Seek from current position.  */
@@ -446,7 +448,7 @@ typedef uLong FAR uLongf;
 #  define z_off_t long
 #endif
 
-#if !defined(_WIN32) && (defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0)
+#if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
 #  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
diff --git a/zconf.h.in b/zconf.h.in
index 5338de6..af35c38 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -409,6 +409,21 @@ typedef uLong FAR uLongf;
 #  undef _LARGEFILE64_SOURCE
 #endif
 
+#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
+#  define Z_HAVE_UNISTD_H
+#endif
+#ifndef Z_SOLO
+#  if defined(Z_HAVE_UNISTD_H) || defined(LARGEFILE64_SOURCE)
+#    include <unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    ifdef VMS
+#      include <unixio.h>       /* for off_t */
+#    endif
+#    ifndef z_off_t
+#      define z_off_t off_t
+#    endif
+#  endif
+#endif
+
 #if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
 #  define Z_LFS64
 #endif
@@ -421,19 +436,6 @@ typedef uLong FAR uLongf;
 #  define Z_WANT64
 #endif
 
-#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
-#  define Z_HAVE_UNISTD_H
-#endif
-#if (defined(Z_HAVE_UNISTD_H) || defined(Z_LARGE64)) && !defined(Z_SOLO)
-#  include <unistd.h>       /* for SEEK_* and off_t */
-#  ifdef VMS
-#    include <unixio.h>     /* for off_t */
-#  endif
-#  ifndef z_off_t
-#    define z_off_t off_t
-#  endif
-#endif
-
 #if !defined(SEEK_SET) && !defined(Z_SOLO)
 #  define SEEK_SET        0       /* Seek from beginning of file.  */
 #  define SEEK_CUR        1       /* Seek from current position.  */
@@ -444,7 +446,7 @@ typedef uLong FAR uLongf;
 #  define z_off_t long
 #endif
 
-#if !defined(_WIN32) && (defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0)
+#if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
 #  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)