Thanks for the info... This was the first time I ever used CentOS (I set it up in a VM for development for a specific client). I'm more of a FreeBSD guy.
Here is the output. I got from 'ldd' and 'yum'.
$ ldd --version
ldd (GNU libc) 2.12
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.
graemeg@wisadevel ~/devel/fpcpackages/fppdf/utils
$ yum list glibc
Loaded plugins: fastestmirror, refresh-packagekit, security
Determining fastest mirrors
* base: mirror.vorboss.net
* centosplus: mirror.vorboss.net
* contrib: mirror.vorboss.net
* extras: mirror.vorboss.net
* fasttrack: mirror.vorboss.net
* updates: mirror.vorboss.net
base | 3.7 kB 00:00
centosplus | 3.4 kB 00:00
centosplus/primary_db | 2.0 MB 00:00
contrib | 2.9 kB 00:00
extras | 3.4 kB 00:00
fasttrack | 3.3 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 3.7 MB 00:00
Installed Packages
glibc.x86_64 2.12-1.166.el6_7.7 @updates
Available Packages
glibc.i686 2.12-1.192.el6 base
glibc.x86_64 2.12-1.192.el6 base
So it seems I have GLIBC 2.12 installed.
I can also add that I normally compile my own newer FPC versions - because I often require multiple FPC compiler versions, and always install them in my $HOME directory in separate "fpc-x.y.z" directories. Looking inside the ~/devel/fpc-3.0.0/ I can see my usual build script go.sh so I definitely compiled FPC 3.0.0 using the released FPC 2.6.4 (which I probably installed from the official Free Pascal console installer). This almost always reduces the install dependencies too (Linux package managers, 99% of the time have too many restrictive dependencies associated).