Add a link to the GHC API docs from the library haddock index

libraries/Makefile

@@ -321,6 +321,7 @@ ifeq "$(HADDOCK_DOCS)" "YES"
 	$(INSTALL_DIR)                                                     $(DESTDIR)$(html_installed_root)
 	$(INSTALL_DATA)   index.html doc-index*.html                       $(DESTDIR)$(html_installed_root)
 	$(INSTALL_SCRIPT) gen_contents_index                               $(DESTDIR)$(html_installed_root)
+	$(INSTALL_DATA)   prologue.txt                                     $(DESTDIR)$(html_installed_root)
 	# Hacks:
 	$(INSTALL_DATA)   base/dist/doc/html/*/*.css $(DESTDIR)$(html_installed_root)
 	$(INSTALL_DATA)   base/dist/doc/html/*/*.js $(DESTDIR)$(html_installed_root)
@@ -365,7 +366,7 @@ endif
 	echo $(WHERE_AM_I)/ifBuildable/ifBuildable >> $(BIN_DIST_LIST)
 	for FILE in dph/dph-prim-interface/interface/*.h dph/dph/LICENSE; do if [ -f $$FILE ]; then echo $(WHERE_AM_I)/$$FILE >> $(BIN_DIST_LIST); fi; done
 ifeq "$(HADDOCK_DOCS)" "YES"
-	for FILE in gen_contents_index index.html doc-index*.html; do echo $(WHERE_AM_I)/$$FILE >> $(BIN_DIST_LIST); done
+	for FILE in gen_contents_index prologue index.html doc-index*.html; do echo $(WHERE_AM_I)/$$FILE >> $(BIN_DIST_LIST); done
 endif
 
 $(foreach SUBDIR,$(SUBDIRS),binary-dist.library.$(SUBDIR)): \

libraries/gen_contents_index

@@ -27,6 +27,7 @@ done
 # Now create the combined contents and index pages
 $HADDOCK --gen-index --gen-contents -o . \
          -t "Haskell Hierarchical Libraries" \
+         -p "prologue.txt" \
          $HADDOCK_ARGS
 
 # Unhandled Windows help stuff?:

libraries/prologue.txt

+
+This index includes documentation for many Haskell modules.
+
+For documentation on the GHC API, see <ghc/index.html>.
+