Makefile.rules: prevent unnecessary updates of ec_version.h

While working on a different issue it was discovered that
$(out)/RW/board/cr50/board.o is rebuilt every time make is ran, even
if there has been no changes. Further investigation has shown that the
problem is that $(out)/RW/board/cr50/board.o depends on
$(out)/ec_version.h, which is not rebuilt unless something changed,
but is declared .PHONY in Makefile.rules

Turns out the declaration is supposed to be conditional on actual
change in ec_version.h, but the condition is always True. This in turn
was due to the fact that when checking if there is a change, some
relevant make variables (CR50_DEV, CR50_SQA, and CRYPTO_TEST) were not
set when invoking ./util/getversion.sh.

When the variables are set, ec_version.h is not decalred PHONY, no
unnecessary compilation is invoked.

BUG=none
TEST=repetitive running of

  make BOARD=cr50 CR50_DEV=1 build/cr50/RW/board/cr50/board.o

   does not trigger recompilation of board.o any more

Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Change-Id: Ibe75bcda9a774e748f973d85841bbde9c29fd104
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2108920
Reviewed-by: Namyoon Woo <namyoon@chromium.org>
Reviewed-by: Andrey Pronin <apronin@chromium.org>

0 files changed, 0 insertions, 0 deletions