[FFmpeg-user] Where does ffmpeg oonfigure looking for libraries?

[Hervé Pellan]

System: CentOS release 6.5 / 2.6.32-431.20.3.el6.x86_64

Hello,

I'm trying to complile a newer version of ffmpeg, with the same options
shown in the pre-installed version on my system.

Ffmpeg sources have been downloaded from git yesterday. So, I assume this
is fresh material.

When I start "./configure", almost all options like "--enable-gnutls"
"--enable-libass" "--enable-libx264" etc, failed with "error: <xxxx> not
found".

But all packages and libraries concerning these options are installed and
present in the system:
/usr/lib64/libgnutls.so.26
/usr/lib64/libass.so.4.1.0
/usr/lib64/libx264.so.120

I've tried to refine generic options of configure like
"--libdir=/usr/lib64" "--arch=x86_64", but it doesn't change anything...

Right now, I don't get it! I don't understand where configure is looking
for these libs?

Do you have any advice or option that should be passed to configure so that
it find librairies which are well installed in the system?

Thanks.