xpcomglue_s_nomozalloc.lib compiled with wchar_t as builtin type

Hi,

I am trying to compile my addons with the latest xulrunner 7.0 and
encountering linker errors.
I just check the the xpcomglue_s_nomozalloc.lib file for sdk/
xulrunner-7.0a2.en-US.win32. I can see that its built with a different
configuration than version 6.0.

In version 6.0 library
definition           :BeginReading@nsAString@@QBEPBGXZ    ("/
Zc:wchar_t-")
Whereas in  version 7.0 definition
is  :BeginReading@nsAString@@QBEPB_WXZ

I am pretty sure that this means that in 7.0, it was built with
builtin wchar_t (WXZ)  whereas the version 6.0 it is built with no
builtin wchar_t(GXZ).

Is this intentional? Any reason for this?