acpi: fix build with new iasl compiler

iasl versions starting with 20120320
(git commit 7fd09d993580e22a096a1b21d2a356d89e702153) enable
a preprocessor by default, which currently strips out
comments from the input. Happily the next release,
20120420, includes an option to disable the preprocessor.
Test and use this option when available.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/Makefile b/Makefile
index dfdec5c462ee1f2ec982be67676b576f088ff499..849824d28c3012626d9fa91bd0f08414f2144f94 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -221,11 +221,14 @@ $(OUT)vgabios.bin: $(OUT)vgabios.bin.raw tools/buildrom.py
 
 ################ DSDT build rules
 
+iasl-option=$(shell if "$(1)" "$(2)" -h > /dev/null 2>&1 \
+    ; then echo "$(2)"; else echo "$(3)"; fi ;)
+
 $(OUT)%.hex: src/%.dsl ./tools/acpi_extract_preprocess.py ./tools/acpi_extract.py
        @echo "  Compiling IASL $@"
        $(Q)cpp -P $< > $(OUT)$*.dsl.i.orig
        $(Q)$(PYTHON) ./tools/acpi_extract_preprocess.py $(OUT)$*.dsl.i.orig > $(OUT)$*.dsl.i
-       $(Q)$(IASL) -vs -l -tc -p $(OUT)$* $(OUT)$*.dsl.i
+       $(Q)$(IASL) $(call iasl-option,$(IASL),-Pn,) -vs -l -tc -p $(OUT)$* $(OUT)$*.dsl.i
        $(Q)$(PYTHON) ./tools/acpi_extract.py $(OUT)$*.lst > $(OUT)$*.off
        $(Q)cat $(OUT)$*.off > $@