[build] Use $(shell ...) to invoke BUILD_ID_CMD

When using $(shell), make will first invoke BUILD_ID_CMD and then have
the value defined when calling $(LD).  This means we get to see the
_build_id when building with make V=1.  Previously the build_id was
figured out as a subshell command run during the recipe execution
without being able to see the build_id itself.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index fc0850b1d467382ae386021970d60b280feaee2a..81bd3c450e2f9421626458346ec33acb694aba87 100644 (file)
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -1199,7 +1199,7 @@ $(BIN)/version.%.o : core/version.c $(MAKEDEPS) $(GIT_INDEX)
 $(BIN)/%.tmp : $(BIN)/version.%.o $(BLIB) $(MAKEDEPS) $(LDSCRIPT)
        $(QM)$(ECHO) "  [LD] $@"
        $(Q)$(LD) $(LDFLAGS) -T $(LDSCRIPT) $(TGT_LD_FLAGS) $< $(BLIB) -o $@ \
-               --defsym _build_id=`$(BUILD_ID_CMD)` \
+               --defsym _build_id=$(shell $(BUILD_ID_CMD)) \
                --defsym _build_timestamp=$(BUILD_TIMESTAMP) \
                -Map $(BIN)/$*.tmp.map
        $(Q)$(OBJDUMP) -ht $@ | $(PERL) $(SORTOBJDUMP) >> $(BIN)/$*.tmp.map