diff --git a/dlls/mshtml/persist.c b/dlls/mshtml/persist.c
index 3bef7a59851..ae883a0846a 100644
--- a/dlls/mshtml/persist.c
+++ b/dlls/mshtml/persist.c
@@ -301,10 +301,6 @@ static HRESULT WINAPI PersistMoniker_Load(IPersistMoniker *iface, BOOL fFullyAva
     if(pibc) {
         IUnknown *unk = NULL;
 
-        static WCHAR wszClientSiteParam[] = {'{','d','4','d','b','6','8','5','0','-',
-            '5','3','8','5','-','1','1','d','0','-','8','9','e','9','-','0','0','a',
-            '0','c','9','0','a','9','0','a','c','}',0};
-
         /* FIXME:
          * Use params:
          * "__PrecreatedObject"
@@ -317,7 +313,7 @@ static HRESULT WINAPI PersistMoniker_Load(IPersistMoniker *iface, BOOL fFullyAva
          * "_EnumFORMATETC_"
          */
 
-        IBindCtx_GetObjectParam(pibc, wszClientSiteParam, &unk);
+        IBindCtx_GetObjectParam(pibc, (LPOLESTR)SZ_HTML_CLIENTSITE_OBJECTPARAM, &unk);
         if(unk) {
             IOleClientSite *client = NULL;
 
diff --git a/dlls/mshtml/tests/htmldoc.c b/dlls/mshtml/tests/htmldoc.c
index e4c638b9234..fee6565554f 100644
--- a/dlls/mshtml/tests/htmldoc.c
+++ b/dlls/mshtml/tests/htmldoc.c
@@ -34,7 +34,6 @@
 
 #include "initguid.h"
 DEFINE_SHLGUID(CGID_Undocumented, 0x000214D4L, 0, 0);
-DEFINE_GUID(CGID_MSHTML, 0xDE4BA900,0x59CA,0x11CF,0x95,0x92, 0x44,0x45,0x53,0x54,0x00,0x00);
 
 #define DEFINE_EXPECT(func) \
     static BOOL expect_ ## func = FALSE, called_ ## func = FALSE
@@ -1262,9 +1261,6 @@ static void test_Load(IPersistMoniker *persist)
     IBindCtx *bind;
     HRESULT hres;
 
-    static WCHAR wszClientSiteParam[] = {'{','d','4','d','b','6','8','5','0','-',
-        '5','3','8','5','-','1','1','d','0','-','8','9','e','9','-','0','0','a',
-        '0','c','9','0','a','9','0','a','c','}',0};
     static const WCHAR wszWineHQ[] =
         {'h','t','t','p',':','/','/','w','w','w','.','w','i','n','e','h','q','.','o','r','g','/',0};
 
@@ -1274,7 +1270,8 @@ static void test_Load(IPersistMoniker *persist)
         return;
 
     CreateBindCtx(0, &bind);
-    IBindCtx_RegisterObjectParam(bind, wszClientSiteParam, (IUnknown*)&ClientSite);
+    IBindCtx_RegisterObjectParam(bind, (LPOLESTR)SZ_HTML_CLIENTSITE_OBJECTPARAM,
+                                 (IUnknown*)&ClientSite);
 
     SET_EXPECT(GetHostInfo);
     SET_EXPECT(GetOptionKeyPath);
diff --git a/include/mshtmhst.idl b/include/mshtmhst.idl
index 1ed8b90b02d..41c3ed0b0a9 100644
--- a/include/mshtmhst.idl
+++ b/include/mshtmhst.idl
@@ -48,6 +48,17 @@ cpp_quote("#define HTMLDLG_VERIFY          0x0100")
 cpp_quote("#define PRINT_DONTBOTHERUSER     0x0001")
 cpp_quote("#define PRINT_WAITFORCOMPLETION  0x0002")
 
+cpp_quote("DEFINE_GUID(CGID_MSHTML, 0xde4ba900,0x59ca,0x11cf,0x95,0x92,0x44,0x45,0x53,0x54,0x00,0x00);")
+cpp_quote("#define CMDSETID_Forms3 CGID_MSHTML")
+
+cpp_quote("#if defined(__GNUC__)")
+cpp_quote("#define SZ_HTML_CLIENTSITE_OBJECTPARAM (const WCHAR[]) {'{','d','4','d','b','6','8','5','0','-','5','3','8','5','-','1','1','d','0','-','8','9','e','9','-','0','0','a','0','c','9','0','a','9','0','a','c','}',0}")
+cpp_quote("#elif defined(_MSC_VER)")
+cpp_quote("#define SZ_HTML_CLIENTSITE_OBJECTPARAM L\"{d4db6850-5385-11d0-89e9-00a0c90a90ac}\"")
+cpp_quote("#else")
+cpp_quote("static const WCHAR SZ_HTML_CLIENTSITE_OBJECTPARAM[] = {'{','d','4','d','b','6','8','5','0','-','5','3','8','5','-','1','1','d','0','-','8','9','e','9','-','0','0','a','0','c','9','0','a','9','0','a','c','}',0};")
+cpp_quote("#endif")
+
 cpp_quote("#ifndef __IHTMLWindow2_FWD_DEFINED__")
 cpp_quote("#define __IHTMLWindow2_FWD_DEFINED__")
 cpp_quote("typedef interface IHTMLWindow2 IHTMLWindow2;")
@@ -195,6 +206,8 @@ interface IDocHostUIHandler : IUnknown
         [out] IDataObject **ppDORet);
 }
 
+cpp_quote("DEFINE_GUID(CGID_DocHostCommandHandler,0xf38bc242,0xb950,0x11d1,0x89,0x18,0x00,0xc0,0x4f,0xc2,0xc8,0x36);")
+
 [
     object,
     uuid(3050F6D0-98b5-11CF-BB82-00AA00BDCE0B),