alex@griever:~/x264$ ls
AUTHORS       config.mak  doc-pak  libx264.a   x264           x264.h
common        config.sub  encoder  Makefile    x264.c         x264.o
config.guess  configure   extras   output      x264cli.h      x264.pc
config.h      COPYING     filters  tools       x264_config.h  x264res.rc
config.log    doc         input    version.sh  x264dll.c
alex@griever:~/x264$ ls
AUTHORS       config.mak  doc-pak  libx264.a   x264           x264.h
common        config.sub  encoder  Makefile    x264.c         x264.o
config.guess  configure   extras   output      x264cli.h      x264.pc
config.h      COPYING     filters  tools       x264_config.h  x264res.rc
config.log    doc         input    version.sh  x264dll.c
alex@griever:~/x264$ install
install: missing file operand
Try `install --help' for more information.
alex@griever:~/x264$ sudo make install
install -d /usr/local/bin
install x264 /usr/local/bin
alex@griever:~/x264$ cd ~/ffmpeg/
alex@griever:~/ffmpeg$ ls
arch.mak                COPYING.LGPLv3  libavcodec     LICENSE
Changelog               CREDITS         libavdevice    MAINTAINERS
cmdutils.c              doc             libavfilter    Makefile
cmdutils_common_opts.h  Doxyfile        libavformat    mt-work
cmdutils.h              ffmpeg.c        libavresample  presets
common.mak              ffplay.c        libavutil      README
configure               ffpresets       libpostproc    RELEASE
COPYING.GPLv2           ffprobe.c       library.mak    tests
COPYING.GPLv3           ffserver.c      libswresample  tools
COPYING.LGPLv2.1        INSTALL         libswscale     version.sh
alex@griever:~/ffmpeg$ /configure --enable-gpl --enable-libx264
bash: /configure: No such file or directory
alex@griever:~/ffmpeg$ cd
alex@griever:~$ cd x264/
alex@griever:~/x264$ ldconfig
/sbin/ldconfig.real: Can't create temporary cache file /etc/ld.so.cache~: Permission denied
alex@griever:~/x264$ sudo ldconfig
alex@griever:~/x264$ cd ~/ffmpeg/
alex@griever:~/ffmpeg$ ./configure --enable-gpl --enable-libx264
ERROR: libx264 not found

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
solving the problem.