Merge changes I801cea04,I4abb6c9d,I3c1cc0ec,I1b6f69ad,Ic4086a1f into integration

* changes:
refactor(build): pass TF_CFLAGS to the assembler
refactor(build): absorb CFLAGS into TF_CFLAGS
refac

Merge changes I801cea04,I4abb6c9d,I3c1cc0ec,I1b6f69ad,Ic4086a1f into integration

* changes:
refactor(build): pass TF_CFLAGS to the assembler
refactor(build): absorb CFLAGS into TF_CFLAGS
refactor(build): use a standard rule to run the preprocessor
refactor(build): place all cflags setting in one place
refactor(build): simplify ENABLE_LTO checking

show more ...

refactor(build): use a standard rule to run the preprocessor

There are a few, functionally identical, ways to call the preprocessor
on a non-C file, depending on the file. They differ in subtle, not

refactor(build): use a standard rule to run the preprocessor

There are a few, functionally identical, ways to call the preprocessor
on a non-C file, depending on the file. They differ in subtle, not
entirely correct, ways - one is missing a dependency to the makefiles,
another generates its .d inline, and the prints are different. That has
resulted in platforms reimplementing this functionality, making the
build brittle - a change to the overall build system doesn't propagate.
So add a MAKE_PRE macro that will make a rule with all the bells and
whistles to run the preprocessor on an arbitrary file.

This patch converts the arm platforms' cot_descriptors DTS rules. The
files are renamed to fit with the build rule and all extra flags are
dropped. Those flags are only necessary for building BL2 c files, which
will be passed to the output C file. Only the DTS flags are needed for
the preprocessing step, which will be passed automatically.

Change-Id: I3c1cc0ecf93b87d828f868214928c1bc9bcb5758
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>

show more ...