title: Warning "i686-mingw32-pkg-config not found, library detection may fail" while cross compiling ffmpeg
body: <p>I get the following warning while trying to cross compile ffmpeg as below</p>
  
  <pre><code>$ ./configure --enable-gpl --enable-version3 --enable-libgsm --enable-libvorbis --enable-libtheora --enable-libspeex --enable-libmp3lame --enable-libopenjpeg --enable-libopencore_amrwb --enable-libopencore_amrnb --arch=x86 --enable-runtime-cpudetect --enable-static --disable-shared --enable-libxvid --enable-libx264 --target-os=mingw32 --enable-avisynth --enable-w32threads --cross-prefix=i686-mingw32- --cc='i686-mingw32-gcc' --enable-memalign-hack --disable-doc --enable-avfilter --disable-ffplay --disable-ffserver --disable-ffprobe
  </code></pre>
  
  <p>Configure ran fine but with the following warning</p>
  
  <pre><code>License: GPL version 3 or later
  Creating config.mak and config.h...
  libavutil/avconfig.h is unchanged
  
  WARNING: i686-mingw32-pkg-config not found, library detection may fail.
  </code></pre>
  
  <p>How do I provide <code>i686-mingw32-pkg-config</code> to configure?</p>