patch 9.1.0337: Missing entry for XDG vimrc file in :version

Problem:  Missing entry for XDG vimrc file in :version
Solution: Add 4th user vimrc entry to :version output
          (Diego Viola)

related: #14182
closes: #14569

Signed-off-by: Diego Viola <diego.viola@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/os_unix.h b/src/os_unix.h
index d214a4a..67dad2e 100644
--- a/src/os_unix.h
+++ b/src/os_unix.h
@@ -250,9 +250,9 @@
 #endif
 
 #ifndef XDG_VIMRC_FILE
-# define XDG_VIMRC_FILE mch_getenv("XDG_CONFIG_HOME") \
-	? (char_u *)"$XDG_CONFIG_HOME/vim/vimrc" \
-	: (char_u *)"~/.config/vim/vimrc"
+# define XDG_VIMRC_FILE (mch_getenv("XDG_CONFIG_HOME") \
+	? "$XDG_CONFIG_HOME/vim/vimrc" \
+	: "~/.config/vim/vimrc")
 #endif
 
 #if !defined(USR_VIMRC_FILE3) && defined(VMS)