[doxygen] Added support for doxygen external search.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189509 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/Makefile b/docs/Makefile
index 2608046..0723ac9 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -19,7 +19,11 @@
 	  -e 's/@abs_srcdir@/./g' \
 	  -e 's/@DOT@/dot/g' \
 	  -e 's/@PACKAGE_VERSION@/mainline/' \
-	  -e 's/@abs_builddir@/./g' > $@
+	  -e 's/@abs_builddir@/./g' \
+	  -e 's/@enable_searchengine@/NO/g' \
+          -e 's/@enable_server_based_search@/NO/g' \
+	  -e 's/@enable_external_search@/NO/g' \
+	  -e 's/@extra_search_mappings@/NO/g' > $@
 endif
 
 include $(CLANG_LEVEL)/Makefile