on slackware64-current:
“configure --disable-ffmpeg” ended with:
configure: LAME library is available as system library.
configure: Figuring out what libraries to enable
configure: Using SYSTEM libraries for LIBVORBIS
configure: Using SYSTEM libraries for LIBMAD
configure: Using SYSTEM libraries for LIBSNDFILE
configure: Using SYSTEM libraries for LIBFLAC
configure: Using SYSTEM libraries for LIBID3TAG
configure: Using LOCAL libraries for LIBSOXR
configure: Using LOCAL libraries for LIBRESAMPLE
configure: Using SYSTEM libraries for LIBSAMPLERATE
configure: Using LOCAL libraries for LIBSBSMS
configure: disabling LIBSOUNDTOUCH
configure: Using LOCAL libraries for LIBNYQUIST
configure: Using LOCAL libraries for LIBVAMP
configure: Using SYSTEM libraries for LIBEXPAT
configure: Using SYSTEM libraries for LIBTWOLAME
configure: Using SYSTEM libraries for FFMPEG
configure: Using LOCAL libraries for PORTSMF
configure: Using LOCAL libraries for PORTAUDIO
configure: Using SYSTEM libraries for LAME
checking build system type… x86_64-unknown-linux-gnu
checking host system type… x86_64-unknown-linux-gnu
checking for library containing dlopen… no
./configure: line 410: test: required: integer expression expected
configure: error: by
./configure: line 299: return: required: numeric argument required
./configure: line 309: exit: required: numeric argument required