Static linking seems broken on FreeBSD

[twvd]

See twvd/snow#49

When features 'static-link' and 'use-pkgconfig' are enabled, linking fails on FreeBSD:

= note: ld: error: unable to find library -l/usr/local/lib/libX11.so
          ld: error: unable to find library -l/usr/local/lib/libXext.so
          ld: error: unable to find library -l/usr/local/lib/libXcursor.so
          ld: error: unable to find library -l/usr/local/lib/libXi.so
          ld: error: unable to find library -l/usr/local/lib/libXfixes.so
          ld: error: unable to find library -l/usr/local/lib/libXrandr.so
          ld: error: unable to find library -l/usr/local/lib/libXss.so
          ld: error: unable to find library -l/usr/local/lib/libinotify.so
          cc: error: linker command failed with exit code 1 (use -v to see invocation)
         

Disabling the 'static-link' resolves the issue