BaseTools GCC: use 'gcc' as the linker command for GCC44 and later

BaseTools GCC: use 'gcc' as the linker command for GCC44 and later

To accommodate upcoming GCCx toolchain versions that require 'gcc' to
be used as the linker in order to support LTO, switch GCC44 and later
(including CLANG35) to a new DLINK build rule that invokes 'gcc' as the
linker instead of 'ld'. Since gcc expects its command line arguments in
a different format, and expects arguments that it needs to pass to the
linker to be prefixed with '-Wl,', this involves changes to most of the
DLINK_FLAGS definitions in tools_def.template, as well as some changes to
module .INF files that set their own linker options.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>