diff --git a/contrib/blast/blast.c b/contrib/blast/blast.c
index e6e65907..c5425ef2 100644
--- a/contrib/blast/blast.c
+++ b/contrib/blast/blast.c
@@ -29,7 +29,7 @@
  *                      - Enable the provision of initial input to blast()
  */
 
-#include <stddef.h>             /* for NULL */
+#include <stddef.h>
 #include <setjmp.h>             /* for setjmp(), longjmp(), and jmp_buf */
 #include "blast.h"              /* prototype for blast() */
 
diff --git a/contrib/minizip/unzip.c b/contrib/minizip/unzip.c
index bcfb9416..ee5cc8ee 100644
--- a/contrib/minizip/unzip.c
+++ b/contrib/minizip/unzip.c
@@ -74,9 +74,9 @@
 
 #include "zlib.h"
 #include "unzip.h"
+#include <stddef.h>
 
 #ifdef STDC
-#  include <stddef.h>
 #  include <string.h>
 #  include <stdlib.h>
 #endif
diff --git a/contrib/minizip/zip.c b/contrib/minizip/zip.c
index 44e88a9c..7947dd61 100644
--- a/contrib/minizip/zip.c
+++ b/contrib/minizip/zip.c
@@ -28,9 +28,9 @@
 #include <time.h>
 #include "zlib.h"
 #include "zip.h"
+#include <stddef.h>
 
 #ifdef STDC
-#  include <stddef.h>
 #  include <string.h>
 #  include <stdlib.h>
 #endif
diff --git a/gzguts.h b/gzguts.h
index fc712dc4..9186f0b2 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -30,10 +30,7 @@
 #  define _POSIX_SOURCE
 #endif
 #include <fcntl.h>
-
-#ifdef _WIN32
-#  include <stddef.h>
-#endif
+#include <stddef.h>
 
 #if defined(__TURBOC__) || defined(_MSC_VER) || defined(_WIN32)
 #  include <io.h>
diff --git a/zconf.h b/zconf.h
index 5e1d68a0..43954026 100644
--- a/zconf.h
+++ b/zconf.h
@@ -237,6 +237,8 @@
 #  define z_const
 #endif
 
+#include <stddef.h>
+
 #ifdef Z_SOLO
    typedef unsigned long z_size_t;
 #else
@@ -244,7 +246,6 @@
 #  if defined(NO_SIZE_T)
      typedef unsigned NO_SIZE_T z_size_t;
 #  elif defined(STDC)
-#    include <stddef.h>
      typedef size_t z_size_t;
 #  else
      typedef unsigned long z_size_t;
@@ -451,11 +452,7 @@ typedef uLong FAR uLongf;
 #  endif
 #endif
 
-#ifdef _WIN32
-#  ifndef Z_SOLO
-#    include <stddef.h>         /* for wchar_t */
-#  endif
-#endif
+#include <stddef.h>
 
 /* a little trick to accommodate both "#define _LARGEFILE64_SOURCE" and
  * "#define _LARGEFILE64_SOURCE 1" as requesting 64-bit operations, (even
diff --git a/zutil.h b/zutil.h
index 14277bcf..bd6375c4 100644
--- a/zutil.h
+++ b/zutil.h
@@ -20,11 +20,9 @@
 #endif
 
 #include "zlib.h"
+#include <stddef.h>
 
 #if defined(STDC) && !defined(Z_SOLO)
-#  if !(defined(_WIN32_WCE) && defined(_MSC_VER))
-#    include <stddef.h>
-#  endif
 #  include <string.h>
 #  include <stdlib.h>
 #endif