pkg-config --libs --cflags libavutil

Package libavutil was not found in the pkg-config search path.
Perhaps you should add the directory containing `libavutil.pc’
to the PKG_CONFIG_PATH environment variable

locate libavutil //找不到libavutil.pc，添加不了路径

/usr/lib/x86_64-linux-gnu/libavutil.so.55
/usr/lib/x86_64-linux-gnu/libavutil.so.55.78.100
/usr/share/doc/libavutil55
/usr/share/doc/libavutil55/changelog.Debian.gz
/usr/share/doc/libavutil55/copyright
/usr/share/lintian/overrides/libavutil55
/var/lib/dpkg/info/libavutil55:amd64.list
/var/lib/dpkg/info/libavutil55:amd64.md5sums
/var/lib/dpkg/info/libavutil55:amd64.shlibs
/var/lib/dpkg/info/libavutil55:amd64.triggers