If you are installing ffmpeg from the SVN and getting the following error log after running ./configure:
./configure
Unable to create and execute files in /tmp. Set the TMPDIR environment
variable to another directory and make sure that /tmp is not mounted
noexec.
Sanity test failed.
If you think configure made a mistake, make sure you are using the latest
version from SVN. If the latest version fails, report the problem to the
ffmpeg-devel@mplayerhq.hu mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file “config.err” produced by configure as this will help
solving the problem.
This means that your /tmp directory has noexec flag and you need to disable it for a while.
Another solution
============
if you are installing as root, make sure you have /root/tmp (you should) and just run
export TMPDIR=$HOME/tmp
before you do your
./configure
make
make install