I've recently compiled MapServer 6.2 on a CentOS 6.3 machine, using

./configure --with-ogr=/usr/bin/gdal-config --with-gdal=/usr/bin/gdal-config --with-proj=/usr --with-geos=/usr/bin/geos-config --with-postgis=/usr/bin/pg_config --with-php=/usr/include/php --with-wfs --with-wfsclient --with-wmsclient --enable-debug --with-threads --with-wcs --with-sos --with-gd --with-freetype=/usr/bin --with-jpeg --with-cairo --with-curl

if that is of interest, anyway.

So after that, Apache/2.2.15 silently fails to restart, i.e. when apachectl graceful, it says "httpd not running, trying to start". There is nothing of interest in the Apache errors_log, /var/log/messages, and it is weird because so far it has always worked.

Restarting the machine multiple times did not solve the problem. Some other stuff I did:

[root@R12X0210 cgi-bin]# service httpd status
httpd is stopped
[root@R12X0210 cgi-bin]# ps aux|grep httpd
root      1846  0.0  0.0 103236   864 pts/0    S+   12:11   0:00 grep httpd

I suspect this might have something to do with a php module that was altered/added by MapServer, but I don't really know... I don't even know how to properly debug this.