Added an initial (mostly stub) implementation of MSHTML.DLL.

diff --git a/configure.ac b/configure.ac
index 05a06df..a7df4ca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1452,6 +1452,7 @@
 dlls/msacm/msg711/Makefile
 dlls/msacm/winemp3/Makefile
 dlls/msdmo/Makefile
+dlls/mshtml/Makefile
 dlls/msi/Makefile
 dlls/msimg32/Makefile
 dlls/msisys/Makefile