Kunnskapsbase

Bajamos php source de:
http://www.php.net/downloads.php
En nuestro caso: PHP 5.1.6 (php-5.1.6.tar.bz2)
Descomprimimos el paquete en /usr/local/src/:
cd /usr/local/src
bzip2 -d php-5.1.6.tar.bz2
tar -xvf php-5.1.6.tar.tar
cd php-5.1.6

Y ahora compilamos el apache a nuestro gusto:

Por ejemplo:
./configure --host=i386-redhat-linux --build=i386-redhat-linux --target=i386-redhat-linux-gnu --program-prefix= --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib --libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/usr/com --mandir=/usr/share/man --infodir=/usr/share/info --cache-file=../config.cache --with-config-file-path=/etc --with-config-file-scan-dir=/etc/php.d --enable-force-cgi-redirect --disable-debug --enable-pic --disable-rpath --enable-inline-optimization --with-bz2 --with-db4=/usr --with-mysql --enable-memory-limit --with-apxs2=/usr/sbin/apxs

O más completo:
./configure --host=i386-redhat-linux --build=i386-redhat-linux --target=i386-redhat-linux-gnu --program-prefix= --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib --libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/usr/com --mandir=/usr/share/man --infodir=/usr/share/info --cache-file=../config.cache --with-config-file-path=/etc --with-config-file-scan-dir=/etc/php.d --enable-force-cgi-redirect --disable-debug --enable-pic --disable-rpath --enable-inline-optimization --with-bz2 --with-db4=/usr --with-curl --with-exec-dir=/usr/bin --with-gettext --with-ncurses --with-gmp --with-iconv --with-jpeg-dir=/usr --with-openssl --with-png --with-pspell --with-regex=system --with-xml --with-expat-dir=/usr --with-dom=shared,/usr --with-dom-xslt=/usr --with-dom-exslt=/usr --with-xmlrpc=shared --with-zlib --with-layout=GNU --enable-bcmath --enable-exif --enable-ftp --enable-magic-quotes --enable-safe-mode --enable-sockets --enable-sysvsem --enable-sysvshm --enable-track-vars --enable-trans-sid --enable-yp --enable-wddx --with-pear=/usr/share/pear --with-imap=shared --with-imap-ssl --with-kerberos --with-ldap=shared --with-mysql=shared,/usr --with-pgsql=shared --with-snmp=shared,/usr --with-snmp=shared --enable-ucd-snmp-hack --with-unixODBC=shared,/usr --enable-memory-limit --enable-bcmath --enable-shmop --enable-calendar --enable-dbx --enable-dio --enable-mcal --enable-mbstring=shared --enable-mbstr-enc-trans --enable-mbregex --with-apxs2=/usr/sbin/apxs

make
make install