--enable-ffmpeg disables ffmpeg use

[jengelh@xxxxxxx (Jan Engelhardt)]

In pjproject-2.4.5, aconfigure.ac reads:


AC_ARG_ENABLE(ffmpeg,
              AC_HELP_STRING([--disable-ffmpeg],
                             [Disable ffmpeg (default: not disabled)]),
>>              [
>>                AC_SUBST(ac_has_ffmpeg,0)
>>                if test "$enable_ffmpeg" = "no"; then
>>                        AC_MSG_RESULT([Checking if ffmpeg is disabled... yes])
>>                fi
>>              ],  

Therefore, whenever one specifies --enable-ffmpeg, it actually
disables it unconditionally, which is like totally backwards.