3 files changed, 12 insertions, 3 deletions

diff --git a/zconf.h b/zconf.h
index 6ad8a04..d3eaf91 100644
--- a/zconf.h
+++ b/zconf.h
@@ -364,8 +364,11 @@ typedef uLong FAR uLongf;
 #  define Z_HAVE_UNISTD_H
 #endif
 
-#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE == 1
+#ifdef STDC
 #  include <sys/types.h>    /* for off_t */
+#endif
+
+#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE
 #  include <unistd.h>       /* for SEEK_* and off_t */
 #  ifdef VMS
 #    include <unixio.h>     /* for off_t */
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index fcd5710..bbe25a7 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -366,8 +366,11 @@ typedef uLong FAR uLongf;
 #  define Z_HAVE_UNISTD_H
 #endif
 
-#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE == 1
+#ifdef STDC
 #  include <sys/types.h>    /* for off_t */
+#endif
+
+#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE
 #  include <unistd.h>       /* for SEEK_* and off_t */
 #  ifdef VMS
 #    include <unixio.h>     /* for off_t */
diff --git a/zconf.h.in b/zconf.h.in
index 6ad8a04..d3eaf91 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -364,8 +364,11 @@ typedef uLong FAR uLongf;
 #  define Z_HAVE_UNISTD_H
 #endif
 
-#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE == 1
+#ifdef STDC
 #  include <sys/types.h>    /* for off_t */
+#endif
+
+#if defined(Z_HAVE_UNISTD_H) || _LARGEFILE64_SOURCE
 #  include <unistd.h>       /* for SEEK_* and off_t */
 #  ifdef VMS
 #    include <unixio.h>     /* for off_t */