updated for version 7.4.235
Problem:    It is not easy to get the full path of a command.
Solution:   Add the exepath() function.
diff --git a/src/proto/os_msdos.pro b/src/proto/os_msdos.pro
index a867f3d..e755211 100644
--- a/src/proto/os_msdos.pro
+++ b/src/proto/os_msdos.pro
@@ -38,7 +38,7 @@
 int mch_setperm __ARGS((char_u *name, long perm));
 void mch_hide __ARGS((char_u *name));
 int mch_isdir __ARGS((char_u *name));
-int mch_can_exe __ARGS((char_u *name));
+int mch_can_exe __ARGS((char_u *name, char_u **path));
 int mch_nodetype __ARGS((char_u *name));
 int mch_dirname __ARGS((char_u *buf, int len));
 int mch_remove __ARGS((char_u *name));