I have openssl-0.9.8e installed in /usr/openssl-0.9.8e, which libraries in /lib and includes in /include/openssl

I have compiled dkim-milter-1.0.0 with:
APPENDDEF(`confLIBS', `-lssl -lcrypto')
APPENDDEF(`confINCDIRS', `-I/usr/openssl-0.9.8e/include/openssl')
APPENDDEF(`confLIBDIRS', `-L/usr/openssl-0.9.8e/lib')

dkim-milter will successfully build and link against the correct libraries:
ldd obj.Linux.2.6.12-1.1381_FC3smp.i686/dkim-filter/dkim-filter
       linux-gate.so.1 =>  (0x00197000)
       libpthread.so.0 => /lib/tls/libpthread.so.0 (0x0086f000)
       libdb-4.2.so => /lib/tls/i686/libdb-4.2.so (0x00c78000)
       libbind.so.3 => /usr/lib/libbind.so.3 (0x00a30000)
       libcrypt.so.1 => /lib/libcrypt.so.1 (0x00817000)
       libnsl.so.1 => /lib/libnsl.so.1 (0x008c6000)
       libdl.so.2 => /lib/libdl.so.2 (0x007dc000)
       libssl.so.0.9.8 => /usr/openssl-0.9.8e/lib/libssl.so.0.9.8 (0x00111000)
       libcrypto.so.0.9.8 => /usr/openssl-0.9.8e/lib/libcrypto.so.0.9.8 (0x002e9000)
       libc.so.6 => /lib/tls/libc.so.6 (0x006af000)
       /lib/ld-linux.so.2 (0x00695000)

However, it refuses to support the rsa-sha256 signing algorithm:
obj.Linux.2.6.12-1.1381_FC3smp.i686/dkim-filter/dkim-filter -V
dkim-filter: Sendmail DKIM Filter v1.0.0
       Compiled with OpenSSL 0.9.8e 23 Feb 2007
       Supported signing algorithms:
               rsa-sha1
       Supported canonicalization algorithms:
               relaxed
               simple
       Supported DKIM versions:
               ietf-base-00
               ietf-base-01
               ietf-base-02
               ietf-base-10
               rfc4871
       Active code options:
               _FFR_QUERY_CACHE
               _FFR_STATS

The version of the openssl binary linked against the same libraries as dkim-filter appears to support sha256:
ldd /usr/openssl-0.9.8e/bin/openssl
       linux-gate.so.1 =>  (0x004ad000)
       libssl.so.0.9.8 => /usr/openssl-0.9.8e/lib/libssl.so.0.9.8 (0x0097d000)
       libcrypto.so.0.9.8 => /usr/openssl-0.9.8e/lib/libcrypto.so.0.9.8 (0x00ee7000)
       libdl.so.2 => /lib/libdl.so.2 (0x007dc000)
       libc.so.6 => /lib/tls/libc.so.6 (0x006af000)
       /lib/ld-linux.so.2 (0x00695000)

echo "test" | /usr/openssl-0.9.8e/bin/openssl dgst -sha256
f2ca1bb6c7e907d06dafe4687e579fce76b37e4e93b7605022da52e6ccc26fd2

Any hints would be greatly appreciated.