There are global requirements but in fact each compoenent as its own requirements :
If you configured with --with-est_enabble=yes which is the option by default, you should specify where to find the Speech_Tools sources : --with-est_sources=<somewhere>
In fact the Speech_Tools headers are needed by PlnUtils. The latter is needed by E.F.M._Client and E.F.M._Server. The --with-plnutils_sources=<somewhere> will tell the system where to find the sources, but if you unpack or download PlnUtils at the same place you unpack/download E.F.M. it will be found automatically.
The --with-festival_sources=<somewhere> tells the system where to find Festival sources which are needed if --with-festival_enable=yes. This is the default behavior and more or less needed if you want http://www.pollock-nageoire.net/gnu/festplugin to be available.
You can indicate where voices can be found: --with-mbrola_voice_sources=<somewhere>.
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