diff --git a/runtime/vim16x16.xpm b/runtime/vim16x16.xpm
index cb75b71..9b55218 100644
--- a/runtime/vim16x16.xpm
+++ b/runtime/vim16x16.xpm
@@ -1,5 +1,5 @@
 /* XPM */
-static char * vim16x16[] = {
+static const char * vim16x16[] = {
 "16 16 8 1",
 " 	c None",
 ".	c #000000",
diff --git a/runtime/vim32x32.xpm b/runtime/vim32x32.xpm
index 43a3a40..017b93b 100644
--- a/runtime/vim32x32.xpm
+++ b/runtime/vim32x32.xpm
@@ -1,5 +1,5 @@
 /* XPM */
-static char * vim32x32[] = {
+static const char * vim32x32[] = {
 "32 32 8 1",
 " 	c None",
 ".	c #000000",
diff --git a/runtime/vim48x48.xpm b/runtime/vim48x48.xpm
index b2fdd95..8bd08bc 100644
--- a/runtime/vim48x48.xpm
+++ b/runtime/vim48x48.xpm
@@ -1,5 +1,5 @@
 /* XPM */
-static char * vim48x48[] = {
+static const char * vim48x48[] = {
 "48 48 8 1",
 " 	c None",
 ".	c #000000",