Sometimes Apache + PHP doesn't like the order in which extensions are loaded.
Especially put recode.so at the front.
What you want to do is remove all the extensions and then add a few at a time (or one at a time), for example, and check that Apache starts. When you find the one that crashes, add the rest, then restart, and finally move the crashing one to the front and restart. This is an issue with FreeBSD at least and I suspect it's the same.
Here's the order on my server with recode before mysql which you can try to mimic first
extension=recode.so
extension=fileinfo.so
extension=tidy.so
extension=tokenizer.so
extension=xmlreader.so
extension=xmlrpc.so
extension=bz2.so
extension=zip.so
extension=zlib.so
extension=mbstring.so
extension=mysql.so
extension=pcre.so
extension=simplexml.so
extension=spl.so
extension=mysqli.so
extension=gd.so
extension=pdf.so
extension=filter.so
extension=mcrypt.so
extension=openssl.so
extension=ctype.so
extension=session.so
extension=sqlite.so
##extension=ldap.so
extension=bcmath.so
extension=calendar.so
extension=curl.so
extension=dom.so
extension=exif.so
extension=ftp.so
extension=xml.so
extension=wddx.so
extension=gettext.so
extension=hash.so
extension=iconv.so
extension=imap.so
extension=json.so
extension=pdo.so
extension=pdo_sqlite.so
extension=posix.so
extension=pspell.so
extension=xmlwriter.so