updated for version 7.3.343
Problem:    No mouse support for urxvt.
Solution:   Implement urxvt mouse support, also for > 252 columns.  (Yiding
            Jia)
diff --git a/src/option.h b/src/option.h
index 1d4d950..21c2753 100644
--- a/src/option.h
+++ b/src/option.h
@@ -819,7 +819,7 @@
 EXTERN char_u	*p_ttym;	/* 'ttymouse' */
 EXTERN unsigned ttym_flags;
 # ifdef IN_OPTION_C
-static char *(p_ttym_values[]) = {"xterm", "xterm2", "dec", "netterm", "jsbterm", "pterm", NULL};
+static char *(p_ttym_values[]) = {"xterm", "xterm2", "dec", "netterm", "jsbterm", "pterm", "urxvt", NULL};
 # endif
 # define TTYM_XTERM		0x01
 # define TTYM_XTERM2		0x02
@@ -827,6 +827,7 @@
 # define TTYM_NETTERM		0x08
 # define TTYM_JSBTERM		0x10
 # define TTYM_PTERM		0x20
+# define TTYM_URXVT		0x40
 #endif
 EXTERN char_u	*p_udir;	/* 'undodir' */
 EXTERN long	p_ul;		/* 'undolevels' */