Delete the MLDS->IL backend.

compiler/mlds_to_il.m:
compiler/mlds_to_ilasm.m:
compiler/mlds_to_managed.m:
compiler/il_peephole.m:
compiler/ilasm.m:
compiler/ilds.m:
    Delete the modules making up the MLDS->IL code generator.

compiler/globals.m:
compiler/prog_data.m:
    Delete IL as a target and foreign language.

compiler/prog_io_pragma.m:
    Delete the max_stack_size/1 foreign proc attribute.  This was only
    ever required by the IL backend.

compiler/options.m
    Delete options used for the IL backend.

compiler/write_deps_file.m:
    Don't generate mmake targets for .il files etc.

compiler/*.m:
    Conform to the above changes.

compiler/notes/compiler_design.html
compiler/notes/work_in_progress.html
    Conform to the above changes.

library/*.m:
    Delete IL foreign_proc and foreign_export pragmas.

README.DotNet:
    Delete this file.

browser/Mmakefile:
compiler/Mmakefile:
deep_profiler/Mmakefile:
mdbcomp/Mmakefile:
mfilterjavac/Mmakefile:
profiler/Mmakefile:
runtime/Mmakefile:
slice/Mmakefile:
    Conform the above changes.

configure.ac:
    Don't check that IL is a supported foreign language when performing the
    up-to-date check.

    Delete the '--enable-dotnet-grades' option.

scripts/Mmake.vars.in:
    Delete variables used for the IL backend (and in on case by the Aditi
    backend).

scripts/Mercury.config.bootstrap.in:
scripts/Mercury.config.in:
scripts/Mmake.rules:
scripts/canonical_grade.sh-subr:
tools/bootcheck:
    Delete stuff related to the 'il' and 'ilc' grades.

doc/reference_manual.texi:
     Delete the documentation of the 'max_stack_size' option.

doc/user_guide.texi:
     Delete stuff related to the IL backend.

tests/hard_coded/csharp_test.{m,exp}:
tests/invalid/foreign_type_missing.{m,err_exp}:
tests/valid/csharp_hello.m:
	Delete these tests: they are no longer relevant.

tests/hard_coded/equality_pred_which_requires_boxing.m:
tests/hard_coded/foreign_import_module.m:
tests/hard_coded/foreign_import_module_2.m:
tests/hard_coded/foreign_type.m:
tests/hard_coded/foreign_type2.m:
tests/hard_coded/foreign_type3.m:
tests/hard_coded/intermod_foreign_type2.m:
tests/hard_coded/lp.m:
tests/hard_coded/user_compare.m:
tests/invalid/foreign_type_2.m:
tests/invalid/foreign_type_missing.{m,err_exp}:
tests/invalid/foreign_type_visibility.m:
tests/invalid/illtyped_compare.{m,err_exp}:
tests/submodules/external_unification_pred.m
tests/valid/big_foreign_type.m
tests/valid/solver_type_bug.m
tests/valid_seq/foreign_type_spec.m
tests/valid_seq/intermod_impure2.m
    Delete IL foreign_procs where necessary.

tests/hard_coded/Mmakefile
tests/invalid/Mercury.options
tests/invalid/Mmakefile
tests/submodules/Mmakefile
tests/valid/Mercury.options
tests/valid/Mmake.valid.common
tests/valid/Mmakefile
tests/valid_seq/Mmakefile
tests/valid_seq/Mercury.options
    Conform to the above changes.

mfilterjavac/Mmakefile

@@ -51,7 +51,7 @@ endif
 
 #-----------------------------------------------------------------------------#
 
-ifneq ("$(filter il% csharp% java% erlang%,$(GRADE))","")
+ifneq ("$(filter csharp% java% erlang%,$(GRADE))","")
 MLOBJS =
 endif
 
@@ -73,7 +73,7 @@ all:	$(ALL_MODULES) $(TAGS_FILE_EXISTS)
 # Add some additional dependencies, so that Mmake knows to remake the
 # profiler if one of the libraries changes.
 
-ifeq ("$(filter il% csharp% java% erlang%,$(GRADE))","")
+ifeq ("$(filter csharp% java% erlang%,$(GRADE))","")
 mfilterjavac:		$(RUNTIME_DIR)/lib$(RT_LIB_NAME).$A
 mfilterjavac:		$(LIBRARY_DIR)/lib$(STD_LIB_NAME).$A
 endif