[FFmpeg-user] confuse error

[y138828]

luodeMac-mini:ffmpeg luonan$ ./configure
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
yasm/nasm not found or too old. Use --disable-yasm for a crippled build.


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 at 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.
luodeMac-mini:ffmpeg luonan$ make
Makefile:2: config.mak: No such file or directory
Makefile:48: /common.mak: No such file or directory
Makefile:91: /libavutil/Makefile: No such file or directory
Makefile:91: /library.mak: No such file or directory
Makefile:168: /doc/Makefile: No such file or directory
Makefile:169: /tests/Makefile: No such file or directory
make: *** No rule to make target `/tests/Makefile'.  Stop.