Top level makefiles need to have the EGREP fix from 6931763

The latest egrep has a problem mixing the -c and -i options, easy workaround in this case.

diff --git a/make/sanity-rules.gmk b/make/sanity-rules.gmk
--- a/make/sanity-rules.gmk
+++ b/make/sanity-rules.gmk
@@ -228,7 +228,7 @@
 ######################################################
 alt_bootdir:
 ifdef ALT_BOOTDIR
- @if [ `$(ECHO) $(subst \,/,$(ALT_BOOTDIR)) | $(EGREP) -ci '^([a-z]:)?/'` -ne 1 ]; then \
+ @if [ `$(ECHO) $(subst \,/,$(ALT_BOOTDIR)) | $(EGREP) -c '^([A-Za-z]:)?/'` -ne 1 ]; then \
          $(ECHO) "ERROR: ALT_BOOTDIR must be an Absolute Path Name, \n" \
            " not a Relative Path Name. \n" \
            " The current value of ALT_BOOTDIR is \n" \