diff --git a/pngconf.h b/pngconf.h
index e11862452..82cd6ef15 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -26,20 +26,23 @@
 #ifdef PNG_SAFE_LIMITS_SUPPORTED
 #  ifdef PNG_USER_WIDTH_MAX
 #    undef PNG_USER_WIDTH_MAX
-#    define PNG_USER_WIDTH_MAX 1000000L
 #  endif
+#  define PNG_USER_WIDTH_MAX 1000000L
+
 #  ifdef PNG_USER_HEIGHT_MAX
 #    undef PNG_USER_HEIGHT_MAX
-#    define PNG_USER_HEIGHT_MAX 1000000L
 #  endif
+#  define PNG_USER_HEIGHT_MAX 1000000L
+
 #  ifdef PNG_USER_CHUNK_MALLOC_MAX
 #    undef PNG_USER_CHUNK_MALLOC_MAX
-#    define PNG_USER_CHUNK_MALLOC_MAX 4000000L
 #  endif
+#  define PNG_USER_CHUNK_MALLOC_MAX 4000000L
+
 #  ifdef PNG_USER_CHUNK_CACHE_MAX
 #    undef PNG_USER_CHUNK_CACHE_MAX
-#    define PNG_USER_CHUNK_CACHE_MAX 128
 #  endif
+#  define PNG_USER_CHUNK_CACHE_MAX 128
 #endif
 
 #ifndef PNG_BUILDING_SYMBOL_TABLE