Você pode obter as opções facilmente assim (você pode procurar no pacote fonte, mas isso é muito menos trabalhoso):
$ sudo apt-get install php5-dev
$ php-config --configure-options
--prefix=/usr --with-apxs2=/usr/bin/apxs2 --with-config-file-path=/etc/php5/apache2
--with-config-file-scan-dir=/etc/php5/apache2/conf.d --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --sysconfdir=/etc --localstatedir=/var --mandir=/usr/share/man
--disable-debug --with-regex=php --disable-rpath --disable-static --with-pic
--with-layout=GNU --with-pear=/usr/share/php --enable-calendar --enable-sysvsem
--enable-sysvshm --enable-sysvmsg --enable-bcmath --with-bz2 --enable-ctype
--with-db4 --without-gdbm --with-iconv --enable-exif --enable-ftp --with-gettext
--enable-mbstring --with-pcre-regex=/usr --enable-shmop --enable-sockets
--enable-wddx --with-libxml-dir=/usr --with-zlib --with-kerberos=/usr
--with-openssl=/usr --enable-soap --enable-zip --with-mhash=yes --with-system-tzdata
--with-mysql-sock=/var/run/mysqld/mysqld.sock --enable-dtrace --without-mm
--with-curl=shared,/usr --with-enchant=shared,/usr --with-zlib-dir=/usr
--with-gd=shared,/usr --enable-gd-native-ttf --with-gmp=shared,/usr
--with-jpeg-dir=shared,/usr --with-xpm-dir=shared,/usr/X11R6
--with-png-dir=shared,/usr --with-freetype-dir=shared,/usr
--with-vpx-dir=shared,/usr --enable-intl=shared --without-t1lib
--with-ldap=shared,/usr --with-ldap-sasl=/usr --with-mysql=shared,/usr
--with-mysqli=shared,/usr/bin/mysql_config --with-pspell=shared,/usr
--with-unixODBC=shared,/usr --with-recode=shared,/usr --with-xsl=shared,/usr
--with-snmp=shared,/usr --with-sqlite3=shared,/usr --with-mssql=shared,/usr
--with-tidy=shared,/usr --with-xmlrpc=shared --with-pgsql=shared,/usr
Veja man php-config
para ainda mais opções.