Build error in src/interfaces

Hi.

I' got followin' error in building libpsql src/interfaces.

make[1]: Entering directory
`/home/Administrator/postgresql-7.4-1/src/interfaces/libpq'
gcc -O2 -fno-strict-aliasing -Wall -Wmissing-prototypes -Wmissing-declaratio
ns -I. -I../../../src/include -I./src/include/port/win32
"-I../../../src/include/port/win32" -DFRONTEND -DSYSCONFDIR='"/usr/local/pg
sql/etc"' -c -o win32.o win32.c
In file included from c:/mingw/include/windows.h:55,
from win32.c:28:
c:/mingw/include/winuser.h:3411: parse error before "BLENDFUNCTION"
win32.c: In function `winsock_strerror':
win32.c:310: warning: long unsigned int format, int arg (arg 4)
win32.c:317: warning: long unsigned int format, int arg (arg 4)
make[1]: *** [win32.o] Error 1
make[1]: Leaving directory
`/home/Administrator/postgresql-7.4-1/src/interfaces/libpq'
make: *** [all] Error 2

Could you give me any hint about this?

Regards.