msxml3: Constify some variables

[Andrew Talbot]

Changelog:
    msxml3: Constify some variables.

diff --git a/dlls/msxml3/domimpl.c b/dlls/msxml3/domimpl.c
index ec89fb4..b0b1cde 100644
--- a/dlls/msxml3/domimpl.c
+++ b/dlls/msxml3/domimpl.c
@@ -174,10 +174,10 @@ static HRESULT WINAPI dimimpl_Invoke(
 
 static HRESULT WINAPI dimimpl_hasFeature(IXMLDOMImplementation* This, BSTR feature, BSTR version, VARIANT_BOOL *hasFeature)
 {
-    static WCHAR bVersion[] = {'1','.','0',0};
-    static WCHAR bXML[] = {'X','M','L',0};
-    static WCHAR bDOM[] = {'D','O','M',0};
-    static WCHAR bMSDOM[] = {'M','S','-','D','O','M',0};
+    static const WCHAR bVersion[] = {'1','.','0',0};
+    static const WCHAR bXML[] = {'X','M','L',0};
+    static const WCHAR bDOM[] = {'D','O','M',0};
+    static const WCHAR bMSDOM[] = {'M','S','-','D','O','M',0};
     BOOL bValidFeature = FALSE;
     BOOL bValidVersion = FALSE;
 
diff --git a/dlls/msxml3/pi.c b/dlls/msxml3/pi.c
index f04affb..a38f355 100644
--- a/dlls/msxml3/pi.c
+++ b/dlls/msxml3/pi.c
@@ -201,7 +201,7 @@ static HRESULT WINAPI dom_pi_put_nodeValue(
 {
     dom_pi *This = impl_from_IXMLDOMProcessingInstruction( iface );
     BSTR sTarget;
-    static WCHAR szXML[] = {'x','m','l',0};
+    static const WCHAR szXML[] = {'x','m','l',0};
     HRESULT hr;
 
     TRACE("%p\n", This );
@@ -526,7 +526,7 @@ static HRESULT WINAPI dom_pi_put_data(
     HRESULT hr = E_FAIL;
     VARIANT val;
     BSTR sTarget;
-    static WCHAR szXML[] = {'x','m','l',0};
+    static const WCHAR szXML[] = {'x','m','l',0};
 
     TRACE("%p %s\n", This, debugstr_w(data) );