In case the build system builds a directory with empty Makefile,
one which does not contain any obj-y entries, the build fails to
link due to missing built-in.o .

This happens because of this part of scripts/Makefile.build
 81 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
 82 builtin-target := $(obj)/built-in.o
 83 endif
which does not assign builtin-target in case obj-y is empty. The
built-in target is then not built at all, and built-in.o is not
generated by this part of scripts/Makefile.build
 325 ifdef builtin-target
 326 quiet_cmd_link_o_target = AR      $@
 327 # If the list of objects to link is empty, just create an empty built-in.o
 ...
 335 targets += $(builtin-target)
 336 endif # builtin-target
This is the correct behavior.

The final link however expects the built-in.o to exist in every directory
included in the build, even in those where the aforementioned code skipped
generation of built-in.o . Make sure the built-in.o does exist for every
directory used in final link simply by doing touch on every built-in.o used
for the link, which will create empty built-in.o in case any built-in.o is
missing.

A possible alternative fix is the always define the builtin-target
and always generate built-in.o .

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Tested-by: Quentin Schulz <quentin.schulz@cherry.de>

Use PHASE_ as the symbol to select a particular XPL build. This means
that SPL_TPL_ is no-longer set.

Update the comment in bootstage to refer to this symbol, instead of
SPL_

Signed-off-by: Simon Glass <sjg@chromium.org>

Use XPL_ as the symbol to indicate an SPL build. This means that SPL_ is
no-longer set.

Signed-off-by: Simon Glass <sjg@chromium.org>

Make this define mean SPL only, not TPL, VPL, etc.

Signed-off-by: Simon Glass <sjg@chromium.org>

Complete this rename for all directories outside arch/ board/ drivers/
and include/

Use the new symbol to refer to any 'SPL' build, including TPL and VPL

Signed-off-by: Simon Glass <sjg@chromium.org>

The new name 'xPL' is intended to indicate a build of any phase which is
not U-Boot proper. Define it for all such phases.

Note that we also define CONFIG_SPL_BUILD for all xPL builds. This
preserves existing behaviour, but future patches will adjust that.

Signed-off-by: Simon Glass <sjg@chromium.org>

Now that the conversion of all CONFIG options to Kconfig is complete,
these files only contain the xPL_BUILD defines. Add a comment to make
this clear.

Signed-off-by: Simon Glass <sjg@chromium.org>

Rename this file to indicate that it refers to any non-U-Boot-proper
phase, not just SPL, which is the phase immediately before U-Boot
proper.

Signed-off-by: Simon Glass <sjg@chromium.org>