Raptor now supports a basic x86 OS build on Windows given the installation
of an appropriate MinGW GCC toolchain (available separately).

This is very much a first cut of the core x86 support, and should be considered
alpha quality, but the fundamentals are now present to build EXE, DLL, IMPLIB
and LIB TARGETTYPEs, as well as most fixed export TARGETTYPEs.  Support for
functionality not directly related to a release build e.g. freezing, assembler
listing, single file compilation etc. is either not yet implemented or
untested, so should not be expected to work correctly.

In order to build components for an x86 configuration, an SBS_GCCX86BIN
environment variable must first be set, with a path as its value, pointing to
the "bin" directory of the MinGW installation intended for use in the build
e.g.:

SBS_GCCX86BIN=C:\apps\MinGW\bin

x86 build configurations should then be available for use as follows:

sbs -c x86
sbs -c x86_urel
sbs -c x86_udeb

A component supports a build using the above x86 configurations if its
bld.inf file has an empty or missing PRJ_PLATFORMS section or PRJ_PLATFORMS is
populated specifically with X86, DEFAULT, BASEDEFAULT or BASEUSERDEFAULT.

The above x86 group and aliases check that the GCC installation is version 3.4.5
but, other than that, it is the end user's responsibility to provide a toolchain
that is suitable for an x86 build; currently the x86 build requires a custom
GCC toolchain that differs from vanilla MinGW releases.

By default, and in common with other Raptor build configurations, x86 build
output locations are architecture rather than toolchain based, therefore the
following output folders are used:

%EPOCROOT%\epoc32\release\x86\lib
%EPOCROOT%\epoc32\release\x86\urel
%EPOCROOT%\epoc32\release\x86\udeb

An optional release_x86gcc variant is available if the output directories need
to differentiate based on the toolchain used.  This variant can be used as
follows:

sbs -c x86.release_x86gcc

...and will lead to the use of these output directories:

%EPOCROOT%\epoc32\release\x86gcc\lib
%EPOCROOT%\epoc32\release\x86gcc\urel
%EPOCROOT%\epoc32\release\x86gcc\udeb