Unset GREP_OPTIONS in build system

Test Plan: GREP_OPTIONS=--blah ./validate

Reviewers: austin, thomie

Reviewed By: thomie

Differential Revision: https://phabricator.haskell.org/D1887

GHC Trac Issues: #11530

Makefile

@@ -18,6 +18,13 @@
 MAKEFLAGS += --no-builtin-rules
 .SUFFIXES:
 
+
+# -----------------------------------------------------------------------------
+# Sanitize environment
+
+# See Trac #11530
+export GREP_OPTIONS :=
+
 ifneq "$(filter maintainer-clean distclean clean clean_% help,$(MAKECMDGOALS))" ""
 -include mk/config.mk
 else

boot

@@ -11,6 +11,9 @@ my %required_tag;
 my $validate;
 my $curdir;
 
+# See Trac #11530
+$ENV{GREP_OPTIONS} = '';
+
 $required_tag{"-"} = 1;
 $validate = 0;
 

ghc.mk

@@ -92,7 +92,7 @@ $(error Your make does not support abspath. You need GNU make >= 3.81)
 endif
 ##################################################
 
-
+# -----------------------------------------------------------------------------
 # Catch make if it runs away into an infinite loop
 ifeq      "$(MAKE_RESTARTS)" ""
 else ifeq "$(MAKE_RESTARTS)" "1"