I compiled php with imap support, I used the latest (pine 4.21) imap libs from washington.
                                          
and somehow the following error results:                                                           

apache version is 1.3.12

# /etc/rc.d/init.d/apachehttpd configtest
Syntax error on line 30 of /usr/local/apache/conf/httpd.conf:
Cannot load /usr/local/apache/libexec/libphp4.so into server:
/usr/local/apache/libexec/libphp4.so: undefined symbol: rfc822_parse_msg_full

also I checked the ldd of libphp.so 

# ldd libphp4.so
        libgdbm.so.2 => /usr/lib/libgdbm.so.2 (0x401b6000)
        libpam.so.0 => /lib/libpam.so.0 (0x401bc000)
        libdl.so.2 => /lib/libdl.so.2 (0x401c4000)
        libmysqlclient.so.8 => /usr/local/mysql/lib/mysql/libmysqlclient.so.8 (0x401c8000)
        libz.so.1 => /usr/local/lib/libz.so.1 (0x401dc000)
        libpng.so.2 => /usr/local/lib/libpng.so.2 (0x401eb000)
        libresolv.so.2 => /lib/libresolv.so.2 (0x40222000)
        libm.so.6 => /lib/libm.so.6 (0x40231000)
        libcrypt.so.1 => /lib/libcrypt.so.1 (0x4024d000)
        libnsl.so.1 => /lib/libnsl.so.1 (0x4027b000)
        libc.so.6 => /lib/libc.so.6 (0x40290000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x2aaaa000)

I found the mistake.

You need to rename c-client.a to libc-client.a

Symlink it...newer versions will try to automatically create the symlink for you, I think.