Andrea, when you do a build so you get 900+ warning messages in the generated "log" file that look like:
/mnt0/build5/cinelerra-5.1/thirdparty/flac-1.4.0/include/FLAC++/export.h:87: warning: Member FLACPP_API_VERSION_CURRENT (macro definition) of group flacpp_export is not documented.
/mnt0/build5/cinelerra-5.1/thirdparty/flac-1.4.0/include/FLAC/metadata.h:408: warning: Illegal command \n as part of a title section
/mnt0/build5/cinelerra-5.1/thirdparty/flac-1.4.0/include/FLAC/metadata.h:1700: warning: Illegal command \n as part of a title section