[PATCH] prevent install(1) from overwritting symlinks

The below patch is designed to keep install(1) from overwriting symbolic
links.   The motivation is if cups is installed some programs still
expect lpr to be in /usr/bin thus when I install cups I backlink the
/usr/local/bin versions of lp* to /usr/bin.   When a build/installworld
is done these links are overwritten and the sym links have to be
performed again.   This patch prevents the overwrite.

This is my very first patch (of any kind [not just for FreeBSD]) so can
people please tell me what I did right and what I did wrong in making
it.   Also tell me what improvements (if any) can be made to the patched
code.

--- src/usr.bin/xinstall/xinstall.c.orig        2007-11-01
18:46:45.000000000 -0400
+++ src/usr.bin/xinstall/xinstall.c     2007-11-01 19:44:43.000000000 -0400
_at__at_ -268,7 +268,7 _at__at_
 void
 install(const char *from_name, const char *to_name, u_long fset, u_int
flags)
 {
-       struct stat from_sb, temp_sb, to_sb;
+       struct stat from_sb, temp_sb, to_sb, to_lsb;
        struct timeval tvb[2];
        int devnull, files_match, from_fd, serrno, target;
        int tempcopy, temp_fd, to_fd;
_at__at_ -299,6 +299,13 _at__at_
        }
 
        target = stat(to_name, &to_sb) == 0;
+       target = lstat(to_name, &to_lsb) == 0;
+
+       if(S_ISLNK(to_lsb.st_mode)) {
+               printf("%s is a symbolic link not modified\n",to_name);
+               errno = EFTYPE;
+               return;
+       }
 
        /* Only install to regular files. */
        if (target && !S_ISREG(to_sb.st_mode)) {