FFmpeg + mingw64：对“ sem_post”的未定义引用

我在使用mingw64编译器构建ffmpeg时遇到问题。这是我的配置：

./configure --prefix=/home/ytan/Dev/build-mingw/ffmpeg/ --enable-cross-compile --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw64 --pkg-config-flags="--static" --enable-shared --disable-static --enable-libvpx --enable-libvorbis --enable-libmp3lame --enable-openssl --enable-pic  --enable-debug --extra-ldlibflags="-static"    

当我运行make时，它在链接期间失败：

(...lot of text omitted)
LD  libavcodec/avcodec-57.dll
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x408d): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x408d): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x4d33): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x4d33): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x6a62): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x6a62): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x8965): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(onyx_if.c.o):(.text+0x8965): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x563): undefined reference to `sched_yield'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x563): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sched_yield'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x16f6): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x16f6): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x174b): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x174b): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x18a9): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x18a9): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x191b): undefined reference to `pthread_create'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x191b): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `pthread_create'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x194e): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x194e): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x19bb): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x19bb): additional relocation overflows omitted from the output
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x19f4): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x220e): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x2224): undefined reference to `pthread_join'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x2252): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x22e8): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x26a2): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(threading.c.o):(.text+0x26d4): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(encodeframe.c.o):(.text+0x1b36): undefined reference to `sched_yield'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(encodeframe.c.o):(.text+0x21a2): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(encodeframe.c.o):(.text+0x24d5): undefined reference to `sched_yield'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(encodeframe.c.o):(.text+0x2757): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(encodeframe.c.o):(.text+0x3259): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x27): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x5d): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x100): undefined reference to `sem_wait'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x2f3): undefined reference to `sched_yield'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x7cb): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x10f9): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x117c): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x11ac): undefined reference to `pthread_create'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x11ef): undefined reference to `pthread_join'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1202): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x120f): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1287): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1294): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x12b7): undefined reference to `pthread_create'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x12e0): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x12f2): undefined reference to `pthread_join'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1305): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1313): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x131b): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1323): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x13f3): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1400): undefined reference to `sem_init'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1423): undefined reference to `pthread_create'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x147e): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x1490): undefined reference to `pthread_join'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14a3): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14ba): undefined reference to `sem_post'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14c8): undefined reference to `pthread_join'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14d4): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14e0): undefined reference to `sem_destroy'
/home/ytan/Dev/build-mingw/libvpx/lib/libvpx.a(ethreading.c.o):(.text+0x14e8): undefined reference to `sem_destroy'
collect2: error: ld returned 1 exit status
library.mak:102: recipe for target 'libavcodec/avcodec-57.dll' failed
make: *** [libavcodec/avcodec-57.dll] Error 1

sem_post似乎指向mingw64编译器使用的pthread，但是将其添加到--host-cflags="-lpthread"没看到帮助。有任何想法吗？

添加--extra-ldlibflags="-pthread"使其工作。我认为这不是因为我在错误的位置添加了它，而是因为我应该使用-pthread而不是-lpthread。它们是有区别的。

现在我的configure命令是这样的：

./configure --prefix=/home/ytan/Dev/build-mingw/ffmpeg/ --enable-cross-compile --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw64 --pkg-config-flags="--static" --enable-shared --disable-static --enable-libvpx --enable-libvorbis --enable-libmp3lame --enable-openssl --enable-pic  --enable-debug --extra-ldlibflags="-static -pthread"