fatal error: ft2build.h: 沒有那個文件或目錄

編譯ffmpeg，出現如下錯誤：

libavfilter/avf_showcqt.c:35:10: fatal error: ft2build.h: 沒有那個文件或目錄
 #include <ft2build.h>
          ^~~~~~~~~~~~
compilation terminated.
make: *** [ffbuild/common.mak:59：libavfilter/avf_showcqt.o] 錯誤 1

解決辦法，修改ffbuild/common.mak：

# NASM requires -I path terminated with /
IFLAGS     := -I/home/quantum6/lib-build/include/SDL2 \
              -I/home/quantum6/lib-build/include \
              -I/home/quantum6/lib-build/include/freetype2 \
              -I. -I$(SRC_LINK)/