When  you compile the FFmpeg package and getting an error  gcc is unable to create an executable file,

Error :

# cd /usr/local/src/ffmpeg

# ./configure 

gcc is unable to create an executable file.
If gcc is a cross-compiler, use the --enable-cross-compile option.
Only do this if you know what cross compiling means.
C compiler test failed.

If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solve the problem.

Solution :

You need to install ffmpeg, ffmpeg-devel packages, so create a repository  dag.repo and add the below lines,
# vim  /etc/yum.repos.d/dag.repo

name=DAG RPM Repository

save and quit :wq!

Now, install GPG-KEY and packages,
# rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt

# yum install ffmpeg ffmpeg-devel ffmpeg-libpostproc