PR modula2/122407: similar error messages are emitted for an unknown symbol

PR modula2/122407: similar error messages are emitted for an unknown symbol

This followup to PR modula2/122241 reduces error message clutter by
filtering unknown symbol error ensuring that only one error message
is emitted for an unknown symbol at a particular location.
The filter is implemented using two binary trees.  A new generic
(based on the address type) binary dictionary module is added to
the base libraries.

gcc/m2/ChangeLog:

	PR modula2/122407
	* Make-lang.in (GM2-LIBS-BOOT-DEFS): Add BinDict.def.
	(GM2-LIBS-BOOT-MODS): Add BinDict.mod.
	(GM2-COMP-BOOT-DEFS): Add FilterError.def.
	(GM2-COMP-BOOT-MODS): Add FilterError.mod.
	(GM2-LIBS-DEFS): Add BinDict.def.
	(GM2-LIBS-MODS): Add BinDict.mod.
	* gm2-compiler/M2Error.def (KillError): New procedure.
	* gm2-compiler/M2Error.mod (WriteFormat3): Reformat.
	(NewError): Rewrite and call AddToList.
	(AddToList): New procedure.
	(SubFromList): Ditto.
	(WipeReferences): Ditto.
	(KillError): Ditto.
	* gm2-compiler/M2LexBuf.mod (MakeVirtualTok): Return
	caret if all token positions are identical.
	* gm2-compiler/M2MetaError.mod (KillError): Import.
	(FilterError): Import.
	(FilterUnknown): New global.
	(initErrorBlock): Initialize symcause and token.
	(push): Capitalize comments.
	(pop): Copy symcause to toblock if discovered.
	(doError): Add parameter sym.
	(defaultError): Assign token if discovered.
	Pass NulSym to doError.
	(updateTokSym): New procedure.
	(chooseError): Call updateTokSym.
	(doErrorScopeModule): Pass sym to doError.
	(doErrorScopeForward): Ditto.
	(doErrorScopeMod): Ditto.
	(doErrorScopeFor): Ditto.
	(doErrorScopeDefinition): Ditto.
	(doErrorScopeDef): Ditto.
	(doErrorScopeProc): Ditto.
	(used): Pass sym[bol] to doError.
	(op): Assign symcause when encountering
	an error, warning or note.
	(MetaErrorStringT1): Rewrite.
	(MetaErrorStringT2): Ditto.
	(MetaErrorStringT3): Ditto.
	(MetaErrorStringT4): Ditto.
	(isUniqueError): New procedure function.
	(wrapErrors): Rewrite.
	(FilterUnknown): Initialize.
	* gm2-compiler/M2Quads.mod (BuildTSizeFunction): Add spell check
	hint specifier.
	* gm2-compiler/FilterError.def: New file.
	* gm2-compiler/FilterError.mod: New file.
	* gm2-libs/BinDict.def: New file.
	* gm2-libs/BinDict.mod: New file.

libgm2/ChangeLog:

	PR modula2/122407
	* libm2pim/Makefile.am (M2MODS): Add BinDict.mod.
	(M2DEFS): Add BinDict.def.
	* libm2pim/Makefile.in: Regenerate.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>