在我详细说明问题之前，我应该让你知道我已经在 heroku 的 bash (heroku run bash) 上成功安装了 ffmpegthumbnailer。
我正在尝试使用我编写的自定义 Heroku buildpack 构建 ffmpegthumbnailer，但是当我在 bin/compile buildpack 文件中运行 ./configure && make install 时，ffmpegthumbnailer 告诉我它找不到 ffmpeg 库（util,格式、编解码器、比例）并建议我设置 PKG_CONFIG_PATH。所以我设置了 PKG_CONFIG_PATH ，它似乎仍然找不到库。
我尝试过以各种方式设置 PKG_CONFIG_PATH。echo export，export，直接通过 PKG_CONFIG_PATH=/app 设置...我一直都是用 .configure 命令设置的。我什至将 PKG_CONFIG_PATH 设置为 heroku config var，并尝试通过作为第三个参数传递到 buildpack 的 ENV_DIR 变量来访问它，但我很快意识到我只是将变量 PKG_CONFIG_PATH 设置为名为 PKG_CONFIG_PATH 的文件的内容，即我正在设置 PKG_CONFIG_PATH=/app/vendor...，我已经完成了！这些都没有奏效。此外，正如您在编译文件和日志中看到的那样， echo $PKG_CONFIG_PATH 会打印正确的路径。
我还能做些什么调试？到底是怎么回事？
下面是我的 bin/compile buildpack 文件，以及我将应用程序部署到 heroku 后的日志。
#!/bin/sh
indent() {
sed -u 's/^/ /'
}
echo "-----> Install ffmpeg-thumbnailer"
BUILD_DIR=$1
VENDOR_DIR="vendor"
DOWNLOAD_URL="https://ffmpegthumbnailer.googlecode.com/files/ffmpegthumbnailer-2.0.8.tar.gz"
echo "DOWNLOAD_URL = " $DOWNLOAD_URL | indent
cd $BUILD_DIR
mkdir -p $VENDOR_DIR
cd $VENDOR_DIR
curl -L --silent $DOWNLOAD_URL | tar xz
cd ffmpegthumbnailer-2.0.8/
export PKG_CONFIG_PATH="$PKG_CONFIG_PATH:/app/vendor/ffmpeg/lib/pkgconfig/"
echo $PKG_CONFIG_PATH
./configure --prefix /app/vendor/ffmpegthumbnailer && make install
echo "exporting PATH and LIBRARY_PATH" | indent
PROFILE_PATH="$BUILD_DIR/.profile.d/ffmpeg-thumbnailer.sh"
mkdir -p $(dirname $PROFILE_PATH)
echo 'export PATH="$PATH:vendor/ffmpeg-thumbnailer/bin"' >> $PROFILE_PATH
echo 'export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:vendor/ffmpeg-thumbnailer/lib"' >> $PROFILE_PATH
还有我的heroku部署日志...
Fetching repository, done.
Counting objects: 5, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 311 bytes, done.
Total 3 (delta 2), reused 0 (delta 0)
-----> Fetching custom git buildpack... done
-----> Multipack app detected
=====> Downloading Buildpack: https://github.com/shunjikonishi/heroku-buildpack-ffmpeg
=====> Detected Framework: ffmpeg
-----> Install ffmpeg
DOWNLOAD_URL = http://flect.github.io/heroku-binaries/libs/ffmpeg.tar.gz
exporting PATH and LIBRARY_PATH
=====> Downloading Buildpack: https://github.com/johnklawlor/heroku-buildpack-ffmpeg-thumbnailer
=====> Detected Framework: ffmpeg
-----> Install ffmpeg-thumbnailer
HERE COMES PKG_CONFIG!
/app/vendor/ffmpeg/lib/pkgconfig
DOWNLOAD_URL = https://ffmpegthumbnailer.googlecode.com/files/ffmpegthumbnailer-2.0.8.tar.gz
/app/vendor/ffmpeg/lib/pkgconfig
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... no
checking for mawk... mawk
checking whether make sets $(MAKE)... yes
checking for g++... g++
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking for style of include used by make... GNU
checking dependency style of g++... gcc3
checking build system type... x86_64-unknown-linux-gnu
checking host system type... x86_64-unknown-linux-gnu
checking how to print strings... printf
checking for gcc... gcc
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking dependency style of gcc... gcc3
checking for a sed that does not truncate output... /bin/sed
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking for fgrep... /bin/grep -F
checking for ld used by gcc... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B
checking the name lister (/usr/bin/nm -B) interface... BSD nm
checking whether ln -s works... yes
checking the maximum length of command line arguments... 1572864
checking whether the shell understands some XSI constructs... yes
checking whether the shell understands "+="... yes
checking how to convert x86_64-unknown-linux-gnu file names to x86_64-unknown-linux-gnu format... func_convert_file_noop
checking how to convert x86_64-unknown-linux-gnu file names to toolchain format... func_convert_file_noop
checking for /usr/bin/ld option to reload object files... -r
checking for objdump... objdump
checking how to recognize dependent libraries... pass_all
checking for dlltool... no
checking how to associate runtime and link libraries... printf %s\n
checking for ar... ar
checking for archiver @FILE support... @
checking for strip... strip
checking for ranlib... ranlib
checking command to parse /usr/bin/nm -B output from gcc object... ok
checking for sysroot... no
checking for mt... mt
checking if mt is a manifest tool... no
checking how to run the C preprocessor... gcc -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if gcc supports -fno-rtti -fno-exceptions... no
checking for gcc option to produce PIC... -fPIC -DPIC
checking if gcc PIC flag -fPIC -DPIC works... yes
checking if gcc static flag -static works... yes
checking if gcc supports -c -o file.o... yes
checking if gcc supports -c -o file.o... (cached) yes
checking whether the gcc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
checking whether -lc should be explicitly linked in... no
checking dynamic linker characteristics... GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking how to run the C++ preprocessor... g++ -E
checking for ld used by g++... /usr/bin/ld -m elf_x86_64
checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes
checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
checking for g++ option to produce PIC... -fPIC -DPIC
checking if g++ PIC flag -fPIC -DPIC works... yes
checking if g++ static flag -static works... yes
checking if g++ supports -c -o file.o... yes
checking if g++ supports -c -o file.o... (cached) yes
checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
checking dynamic linker characteristics... (cached) GNU/Linux ld.so
checking how to hardcode library paths into programs... immediate
checking for special C compiler options needed for large files... no
checking for _FILE_OFFSET_BITS value needed for large files... no
checking whether make supports nested variables... yes
checking for ANSI C header files... (cached) yes
checking for inttypes.h... (cached) yes
checking for sys/stat.h... (cached) yes
checking whether /usr/bin/ld -m elf_x86_64 accepts --as-needed... yes
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for FFMPEG... no
configure: error: Package requirements (libavutil libavformat libavcodec >= 52.26.0 libswscale) were not met:
No package 'libavutil' found
No package 'libavformat' found
No package 'libavcodec' found
No package 'libswscale' found
Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.
Alternatively, you may set the environment variables FFMPEG_CFLAGS
and FFMPEG_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.
exporting PATH and LIBRARY_PATH
=====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-ruby