2 files changed, 4 insertions, 2 deletions

diff --git a/gzguts.h b/gzguts.h
index f162950..6800fa7 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -12,7 +12,8 @@
 #  endif
 #endif
 
-#if ((__GNUC__-0) * 10 + __GNUC_MINOR__-0 >= 33) && !defined(NO_VIZ)
+#define GCC_VER ((__GNUC__-0) * 100 + __GNUC_MINOR__-0)
+#if (GCC_VER >= 303 && !defined(__APPLE__)) || GCC_VER >= 400
 #  define ZLIB_INTERNAL __attribute__((visibility ("hidden")))
 #else
 #  define ZLIB_INTERNAL
diff --git a/zutil.h b/zutil.h
index de42dfb..f422147 100644
--- a/zutil.h
+++ b/zutil.h
@@ -13,7 +13,8 @@
 #ifndef ZUTIL_H
 #define ZUTIL_H
 
-#if ((__GNUC__-0) * 10 + __GNUC_MINOR__-0 >= 33) && !defined(NO_VIZ)
+#define GCC_VER ((__GNUC__-0) * 100 + __GNUC_MINOR__-0)
+#if (GCC_VER >= 303 && !defined(__APPLE__)) || GCC_VER >= 400
 #  define ZLIB_INTERNAL __attribute__((visibility ("hidden")))
 #else
 #  define ZLIB_INTERNAL