diff --git a/src/os_unix.c b/src/os_unix.c
index 3aa397b..a5f033d 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -1734,9 +1734,9 @@
     if (oldicon == NULL && !test_only)
     {
 	if (STRNCMP(T_NAME, "builtin_", 8) == 0)
-	    oldicon = T_NAME + 8;
+	    oldicon = vim_strsave(T_NAME + 8);
 	else
-	    oldicon = T_NAME;
+	    oldicon = vim_strsave(T_NAME);
     }
 
     return retval;
@@ -1939,9 +1939,9 @@
     if (!test_only)
     {
 	if (STRNCMP(T_NAME, "builtin_", 8) == 0)
-	    oldicon = T_NAME + 8;
+	    oldicon = vim_strsave(T_NAME + 8);
 	else
-	    oldicon = T_NAME;
+	    oldicon = vim_strsave(T_NAME);
     }
     return FALSE;
 }