diff --git a/gzguts.h b/gzguts.h
index 593dfee..bb62175 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -39,6 +39,10 @@
 #  include <io.h>
 #endif
 
+#if defined(_WIN32) || defined(__CYGWIN__)
+#  define WIDECHAR
+#endif
+
 #ifdef WINAPI_FAMILY
 #  define open _open
 #  define read _read
diff --git a/gzlib.c b/gzlib.c
index 3e344f9..d735829 100644
--- a/gzlib.c
+++ b/gzlib.c
@@ -188,7 +188,7 @@ local gzFile gz_open(path, fd, mode)
     }
 
     /* save the path name for error messages */
-#ifdef _WIN32
+#ifdef WIDECHAR
     if (fd == -2) {
         len = wcstombs(NULL, path, 0);
         if (len == (size_t)-1)
@@ -202,7 +202,7 @@ local gzFile gz_open(path, fd, mode)
         free(state);
         return NULL;
     }
-#ifdef _WIN32
+#ifdef WIDECHAR
     if (fd == -2)
         if (len)
             wcstombs(state->path, path, len + 1);
@@ -239,7 +239,7 @@ local gzFile gz_open(path, fd, mode)
 
     /* open the file with the appropriate flags (or just use fd) */
     state->fd = fd > -1 ? fd : (
-#ifdef _WIN32
+#ifdef WIDECHAR
         fd == -2 ? _wopen(path, oflag, 0666) :
 #endif
         open((const char *)path, oflag, 0666));
@@ -303,7 +303,7 @@ gzFile ZEXPORT gzdopen(fd, mode)
 }
 
 /* -- see zlib.h -- */
-#ifdef _WIN32
+#ifdef WIDECHAR
 gzFile ZEXPORT gzopen_w(path, mode)
     const wchar_t *path;
     const char *mode;
diff --git a/zlib.h b/zlib.h
index 7ec5fa8..7263beb 100644
--- a/zlib.h
+++ b/zlib.h
@@ -1757,7 +1757,7 @@ ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
 ZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
 ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
 ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
-#if defined(_WIN32) && !defined(Z_SOLO)
+#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
 ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
                                             const char *mode));
 #endif