patch 8.2.4838: checking for absolute path is not trivial

Problem:    Checking for absolute path is not trivial.
Solution:   Add isabsolutepath(). (closes #10303)
diff --git a/src/version.c b/src/version.c
index 2fa8992..1b87213 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4838,
+/**/
     4837,
 /**/
     4836,