diff --git a/zconf.h b/zconf.h
index 5733ed6..fb76ffe 100644
--- a/zconf.h
+++ b/zconf.h
@@ -524,7 +524,7 @@ typedef uLong FAR uLongf;
 #if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
-#  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
+#  if defined(_WIN32) && !defined(__GNUC__)
 #    define z_off64_t __int64
 #  else
 #    define z_off64_t z_off_t
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index 9cc20bf..310c439 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -526,7 +526,7 @@ typedef uLong FAR uLongf;
 #if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
-#  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
+#  if defined(_WIN32) && !defined(__GNUC__)
 #    define z_off64_t __int64
 #  else
 #    define z_off64_t z_off_t
diff --git a/zconf.h.in b/zconf.h.in
index 5733ed6..fb76ffe 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -524,7 +524,7 @@ typedef uLong FAR uLongf;
 #if !defined(_WIN32) && defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
-#  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
+#  if defined(_WIN32) && !defined(__GNUC__)
 #    define z_off64_t __int64
 #  else
 #    define z_off64_t z_off_t