PR modula2/122241 Lack of spelling hints with simple errors

PR modula2/122241 Lack of spelling hints with simple errors

This patch introduces spell checking to Modula-2.  Currently
it spell checks unknown symbols in pass 3.  Unknowns found in
record fields, with statements, procedures and variable names
are checked.

gcc/m2/ChangeLog:

	PR modula2/122241
	* Make-lang.in (GM2_C_OBJS): Add m2/gm2-gcc/m2spellcheck.o.
	(GM2-COMP-BOOT-DEFS): Add M2StackSpell.def.
	(GM2-COMP-BOOT-MODS): Add M2StackSpell.mod.
	(GM2-GCC-DEFS): Add m2spellcheck.def.
	(GM2-COMP-DEFS): Add M2StackSpell.def.
	(GM2-COMP-MODS): Add M2StackSpell.mod.
	* gm2-compiler/M2Base.mod (CheckCompatible): Add comments.
	* gm2-compiler/M2MetaError.mod (importHint): New field.
	(exportHint): Ditto.
	(withStackHint): Ditto.
	* gm2-compiler/M2Quads.mod (M2StackSpell): Import.
	(BuildProcedureCall): Add spell check specifier when
	encountering an unknown symbol.
	(CheckProcedureParameters): Ditto.
	(CheckParameter): Ditto.
	(DescribeType): Ditto.
	(GetQualidentImport): Ditto.
	(BuildValFunction): Ditto.
	(BuildCastFunction): Ditto.
	(BuildConvertFunction): Ditto.
	(ExpectingParameterType): Ditto.
	(ExpectingVariableType): Ditto.
	(BuildDesignatorPointer): Ditto.
	(BuildEmptySet): Ditto.
	(CheckVariableOrConstantOrProcedure): Ditto.
	* gm2-compiler/P2SymBuild.mod (BuildType): Add comment.
	* gm2-compiler/P3Build.bnf (SubDesignator): Reimplement.
	* gm2-compiler/P3SymBuild.mod (P3StartBuildDefModule): Add
	M2StackSpell.Push.
	(P3StartBuildProgModule): Ditto.
	(P3StartBuildImpModule): Ditto.
	(StartBuildInnerModule): Ditto.
	(StartBuildProcedure): Ditto.
	(P3EndBuildDefModule): Add M2StackSpell.Pop.
	(P3EndBuildImpModule): Ditto.
	(P3EndBuildProgModule): Ditto.
	(EndBuildInnerModule): Ditto.
	(EndBuildProcedure): Ditto.
	(BuildProcedureHeading): Ditto.
	(EndBuildForward): Ditto.
	* gm2-compiler/SymbolTable.mod (RequestSym): Reformat.
	* gm2-gcc/init.cc (_M2_M2StackSpell_init): New prototype.
	(init_PerCompilationInit): Call _M2_M2StackSpell_init.
	* gm2-libs/DynamicStrings.def (RemoveWhitePrefix): Correct
	comment.
	* gm2-libs/DynamicStrings.mod (RemoveWhitePrefix): Ditto.
	* gm2-compiler/M2StackSpell.def: New file.
	* gm2-compiler/M2StackSpell.mod: New file.
	* gm2-gcc/m2spellcheck.cc: New file.
	* gm2-gcc/m2spellcheck.def: New file.
	* gm2-gcc/m2spellcheck.h: New file.

gcc/testsuite/ChangeLog:

	* gm2/iso/fail/badfield.mod: New test.
	* gm2/iso/fail/badfield2.mod: New test.
	* gm2/iso/fail/badprocedure.mod: New test.
	* gm2/iso/fail/badprocedure2.mod: New test.
	* gm2/iso/fail/badset4.mod: New test.

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