remove old build conditionals
the old wrapper env vars are no longer applicable to 6.0.0
scripting is no longer optional
though wxPython is still an optional dependency?
add withI18n build option to kicad.base
i18n was moved to the kicad source, and is disabled by default
withI18n takes the same default
add withPCM option
to allow disabling building the Plugin and Content Manager
remove the withOCE option
the build option was removed in upstream commit:
1c5c052301b607a0cf8b8ed6681f1db1622a865b
and unconditionally use wxGTK31-gtk3 and wxPython
the pcb editor's python terminal seems to work with these versions
78f0769183