getpwuid_r causes core dumps

In a recent test our users saw that freetds was core dumping in threadsafe.c.  The following is the issue:

diff -u -r1.1.1.5 -r1.2
--- threadsafe.c        17 Sep 2010 17:11:06 -0000      1.1.1.5
+++ threadsafe.c        15 Nov 2010 22:37:41 -0000      1.2
@@ -516,12 +516,14 @@
 #ifndef _WIN32
 /* if is available getpwuid_r use it */
 #if defined(HAVE_GETUID) && defined(HAVE_GETPWUID_R)
-       struct passwd *pw, bpw;
+       struct passwd *pw = NULL, bpw;
        char buf[1024];

 # if defined(HAVE_FUNC_GETPWUID_R_5)
        if (getpwuid_r(getuid(), &bpw, buf, sizeof(buf), &pw))
                return NULL;
+       if (pw == NULL)
+           return NULL;

 # elif defined(HAVE_FUNC_GETPWUID_R_4_PW)
        if (!(pw = getpwuid_r(getuid(), &bpw, buf, sizeof(buf))))

getpwuid_r can return 0 when a lookup hasn't found a matching entry.
This seems to work for us, but it may be more correct to check errno.

-Peter