Cross-compiling not working

[t1456619]

I tried to Cross-compile this library from linux to windows.
I modified the Makefile (ffmpeg30 part) as follow:

wget -O ffmpeg30.tar.bz2 http://ffmpeg.org/releases/ffmpeg-3.0.8.tar.bz2 mkdir ffmpeg30 && tar xf ffmpeg30.tar.bz2 -C ffmpeg30 --strip-components=1 && cd ffmpeg30 && ./configure --arch=x86 --target-os=mingw32 --cross-prefix=i686-w64-mingw32- --prefix=/usr/local --disable-debug --enable-pthreads --enable-nonfree --enable-gpl --disable-indev=jack && make -j6 && sudo make install

and it all works good but when I try to compile the example with:

GOOS=windows GOARCH=386 CGO_ENABLED=1 CXX=i686-w64-mingw32-g++ CC=i686-w64-mingw32-gcc go build -tags ffmpeg30

i get the following error:

# github.com/imkira/go-libav/avutil /usr/local/lib/libavutil.a(log.o):log.c:(.text+0x1da): undefined reference to 'pthread_mutex_lock' /usr/local/lib/libavutil.a(log.o):log.c:(.text+0x69a): undefined reference to 'pthread_mutex_unlock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x20): undefined reference to 'pthread_mutex_lock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x31): undefined reference to 'pthread_mutex_unlock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x81): undefined reference to 'pthread_mutex_destroy' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x767): undefined reference to 'pthread_mutex_init' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x7f3): undefined reference to 'pthread_mutex_destroy' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x81f): undefined reference to 'pthread_mutex_lock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x8a6): undefined reference to 'pthread_mutex_unlock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x956): undefined reference to 'pthread_mutex_unlock' /usr/local/lib/libavutil.a(buffer.o):buffer.c:(.text+0x968): undefined reference to 'pthread_mutex_unlock' collect2: error: ld returned 1 exit status

so I tried to modify the source adding some CFLAGS:

//#cgo CFLAGS: -pthread //#cgo CFLAGS: -lpthread //#cgo CFLAGS: -pedantic //#cgo CFLAGS: -Wextra //#cgo CFLAGS: -Wall //#include <pthread.h> //#include <lpthread.h> import "C"

I didn't read it was supposed to work on windows nor i did read the opposit tho