CVS tip build failure (win32)

I'm seeing the following failure on win32, post roles patch application:

gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Wold-style-definition -Wendif-labels
-fno-strict-aliasing -I../../../src/include -I./src/include/port/win32
-DEXEC_BACKEND  "-I../../../src/include/port/win32" -DBUILDING_DLL  -c
-o namespace.o namespace.c
In file included from namespace.c:38:
../../../src/include/utils/acl.h:214: error: conflicting types for
'InitializeAcl'
c:/mingw/bin/../lib/gcc/mingw32/3.4.2/../../../../include/winbase.h:1571
: error: previous declaration of 'InitializeAcl' was here
../../../src/include/utils/acl.h:214: error: conflicting types for
'InitializeAcl'
c:/mingw/bin/../lib/gcc/mingw32/3.4.2/../../../../include/winbase.h:1571
: error: previous declaration of 'InitializeAcl' was here
make[3]: *** [namespace.o] Error 1
make[3]: Leaving directory `/cvs/pgsql.dbsize/src/backend/catalog'
make[2]: *** [catalog-recursive] Error 2
make[2]: Leaving directory `/cvs/pgsql.dbsize/src/backend'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/cvs/pgsql.dbsize/src'
make: *** [all] Error 2

That's following a cvs update and a make clean. All was fine before I
updated :-(

Regards, Dave