patch 7.4.1008
Problem:    The OS/2 code pollutes the source while nobody uses it these days.
Solution:   Drop the support for OS/2.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 31b51e9..0e8e7bd 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -3794,7 +3794,7 @@
 
 	/* Check for environment variable */
 	if (*xp->xp_pattern == '$'
-#if defined(MSDOS) || defined(MSWIN) || defined(OS2)
+#if defined(MSDOS) || defined(MSWIN)
 		|| *xp->xp_pattern == '%'
 #endif
 		)
@@ -5073,7 +5073,7 @@
 		 * For Unix and OS/2, when wildcards are expanded, this is
 		 * done by ExpandOne() below.
 		 */
-#if defined(UNIX) || defined(OS2)
+#if defined(UNIX)
 		if (!has_wildcards)
 #endif
 		    backslash_halve(eap->arg);