patch 8.1.0004: test for :compiler command sometimes fails

Problem:    Test for :compiler command sometimes fails.
Solution:   Be less strict about the error message. (Dominique Pelle)
diff --git a/src/version.c b/src/version.c
index 9ceabc7..32ddbf6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4,
+/**/
     3,
 /**/
     2,