diff --git a/Makefile.pl b/Makefile.pl
index 9e69afe..b82ac5f 100755
--- a/Makefile.pl
+++ b/Makefile.pl
@@ -170,13 +170,13 @@ print(OUT
 
 foreach my $l (@library_targets) {
     my $warn = "-Wall -Wextra -Wno-sign-compare";
-    my $s = $l;
-    my $o = $object_suffix;
+    my $s    = $l;
+    my $o    = $object_suffix;
     $o =~ s/\./\\\./g;
     $s =~ s/$o$/.c/;
 
-    if($l =~ /^external\//){
-	    $warn = "";
+    if ($l =~ /^external\//) {
+        $warn = "";
     }
 
     print(OUT "${l}: ${s}\n");
diff --git a/pl/rules.pl b/pl/rules.pl
index 8ad6659..f9915e9 100644
--- a/pl/rules.pl
+++ b/pl/rules.pl
@@ -45,6 +45,10 @@ if (param_get("freetype2")) {
     }
 }
 
+if (param_get("vulkan") && param_get("vulkan-string-helper")) {
+    add_cflags("-DHAS_VK_ENUM_STRING_HELPER");
+}
+
 new_object("src/icon/*.c");
 new_object("src/font/*.c");
 new_object("src/cursor/*.c");