While building openssh-3.6p1 or openssh-3.6.1p1 on Solaris 2.5.1 I get the
following errors:

--
In file included from progressmeter.c:66:
/usr/include/libgen.h:26: conflicting types for `basename'
openbsd-compat/basename.h:9: previous declaration of `basename'
/usr/include/libgen.h:50: conflicting types for `dirname'
openbsd-compat/dirname.h:3: previous declaration of `dirname'
--

and the build fails.

Based on information from the openssh-unix-dev mailing list, I edited config.h
and added "#define HAVE_BASENAME 1" and "#define HAVE_DIRNAME 1".  After doing
this, the compile goes farther only to fail at the following point:

--
gcc -o sshd sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o sshpty.o
sshlogin.o servconf.o serverloop.o uidswap.o auth.o auth1.o auth2.o
auth-options.o session.o auth-chall.o auth2-chall.o groupaccess.o auth-skey.o
auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o auth2-none.o auth2-passwd.o
auth2-pubkey.o monitor_mm.o monitor.o monitor_wrap.o monitor_fdpass.o kexdhs.o
kexgexs.o auth-krb5.o auth-krb4.o loginrec.o auth-pam.o auth2-pam.o auth-sia.o
md5crypt.o -L. -Lopenbsd-compat/ -L/usr/site/openssl/lib -R/usr/site/openssl/lib
-L/usr/site/zlib/lib -R/usr/site/zlib/lib  -L/usr/local/lib -R/usr/local/lib
-lssh -lopenbsd-compat   -lposix4 -lz -lsocket -lnsl  -lcrypto
auth.o: In function `secure_filename':
/home/pancake/benderm/Zip/openssh-3.6.1p1/auth.c:453: undefined reference to
`dirname'
collect2: ld returned 1 exit status
--

If I edit Makefile and add -lgen to LIBS, the compile finishes.

It looks like the configure script needs to check for the existence of basename
and dirname in libgen and adjust the Makefile and config.h accordingly.