Fix for #7879.

Changed copy of utils/haddock/html/resources/html to use "cp -RL" rather than "cp -R". This allows users to run validate in a build tree, where the build tree was setup using lndir with a relative path to the source directory.

ghc.mk

@@ -20,7 +20,7 @@ $(INPLACE_BIN)/$(utils/haddock_dist_PROG): $(INPLACE_LIB)/html $(INPLACE_LIB)/la
 
 $(INPLACE_LIB)/html:
 	$(call removeTrees,$@)
-	"$(CP)" -R utils/haddock/resources/html $@
+	"$(CP)" -RL utils/haddock/resources/html $@
 
 $(INPLACE_LIB)/latex:
 	$(call removeTrees,$@)