Only fail on known-bad grep configurations.
Rather than exit when any grep configuration is set, only fail on ones we know
to be bad. This lets people use benign configuration options such as
--color=auto and --directories=skip.
Bug: 21260618
Change-Id: I3641c7895df4b43e36a983ea6ad877969cd38bf5
diff --git a/core/config.mk b/core/config.mk
index d701f04..66c8afb 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -35,9 +35,9 @@
# only has an effect on python 2.6 and above.
export PYTHONDONTWRITEBYTECODE := 1
-ifneq ($(GREP_OPTIONS),)
+ifneq ($(filter --color=always, $(GREP_OPTIONS)),)
$(warning The build system needs unmodified output of grep.)
-$(error Please unset your $$GREP_OPTIONS.)
+$(error Please remove --color=always from your $$GREP_OPTIONS)
endif
# Standard source directories.