Demangler for MSVC symbols.

Demangler is implemented using the existing LLVM Demangler.
The demangler is built as a separate library (libdemangle_msvc)
due to the licensing issues - normally, it would be integrated
into libiberty.

The library exposes msvc_demangle() call while BFD adds
bfd_demangle_new() which automatically demangles using
libdemangle_msvc or libiberty. GDB now uses bfd_demangle_new()
instead of bfd_demangle(). Binutils that want MSVC demangling
should switch to the new function as well.

For all it's demangling needs, GDB almost exclusively uses
gdb_demangle(), which returns plain demangled string.
However, GDB also has a few places where it demangles into the
demangle_component AST. These functions are not relavant to
PE/COFF binaries and MSVC demangling, however, the appropriate
functions are added for completeness:
msvc_class_name_from_physname() and msvc_method_name_from_physname().

Author: vuzelac

Makefile.def

@@ -143,6 +143,7 @@ host_modules= { module= zlib; no_install=true; no_check=true;
 	        extra_configure_flags='@extra_host_zlib_configure_flags@ @host_libs_picflag@';};
 host_modules= { module= gnulib; };
 host_modules= { module= gdbsupport; };
+host_modules= { module= libdemangle-msvc; };
 host_modules= { module= gdbserver; };
 host_modules= { module= gdb; };
 host_modules= { module= expect; };
@@ -451,6 +452,7 @@ dependencies = { module=all-gdb; on=all-libiberty; };
 dependencies = { module=all-gdb; on=all-libiconv; };
 dependencies = { module=all-gdb; on=all-gnulib; };
 dependencies = { module=all-gdb; on=all-gdbsupport; };
+dependencies = { module=all-gdb; on=all-libdemangle-msvc; };
 dependencies = { module=all-gdb; on=all-opcodes; };
 dependencies = { module=all-gdb; on=all-readline; };
 dependencies = { module=all-gdb; on=all-build-bison; };
@@ -498,6 +500,7 @@ dependencies = { module=configure-binutils; on=configure-gettext; };
 dependencies = { module=all-binutils; on=all-libiberty; };
 dependencies = { module=all-binutils; on=all-opcodes; };
 dependencies = { module=all-binutils; on=all-bfd; };
+dependencies = { module=all-binutils; on=all-libdemangle-msvc; };
 dependencies = { module=all-binutils; on=all-build-flex; };
 dependencies = { module=all-binutils; on=all-build-bison; };
 dependencies = { module=all-binutils; on=all-gettext; };