Add --legend switch for genhtml. This includes small explanation

on webpages. This feature has been in lcov since 1.5.


git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@3766 e5f2f494-b856-4b98-b285-d166d9295462

Makefile.am

@@ -37,7 +37,7 @@ report-coverage:
 			\*_unittest.cc \
 			\*_unittests.h \
 		--output report.info
-	$(GENHTML) -o coverage report.info 
+	$(GENHTML) --legend -o coverage report.info 
 
 coverage: clean-coverage perform-coverage report-coverage