exec: search commands in the current directory first on OS/2

On OS/2, commands(executables) are searched in the current directory
before in $PATH.

    modified:   exec.c

exec.c

@@ -1315,6 +1315,12 @@ search_path(const char *name, const char *lpath,
 		goto search_path_err;
 	}
 
+#ifdef __OS2__
+	/* look in a current directory first (OS/2 style) */
+	if (search_access(name, mode) == 0)
+		goto search_path_ok;
+#endif
+
 	namelen = strlen(name) + 1;
 	Xinit(xs, xp, 128, ATEMP);