i586-mingw32msvc-gcc -DHAVE_CONFIG_H -I. -I. -I.. -I/home/ds/gst/win32/gstreamer-devel/include -D_GNU_SOURCE -DG_LOG_DOMAIN=g_log_domain_gstreamer -DGST_MAJORMINOR=\"0.10\" -DGST_DISABLE_DEPRECATED -I../libs -I.. -I.. -I/home/ds/gst/win32/gstreamer-devel/include/glib-2.0 -I/home/ds/gst/win32/gstreamer-devel/lib/glib-2.0/include -I/home/ds/gst/win32/gstreamer-devel/include/libxml2 -Wall -Werror -g -g -O2 -I/home/ds/gst/win32/gstreamer-devel/include -MT libgstreamer_0.10_la-gstpoll.lo -MD -MP -MF .deps/libgstreamer_0.10_la-gstpoll.Tpo -c gstpoll.c  -DDLL_EXPORT -DPIC -o .libs/libgstreamer_0.10_la-gstpoll.o
In file included from /usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/include/objbase.h:73,
                 from /usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/include/ole2.h:9,
                 from /usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/include/windows.h:114,
                 from gstpoll.c:71:
/usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/include/objidl.h:95: error: expected identifier or ‘(’ before string constant

This is due to the recent addition of "DATADIR" to config.h.  Windows headers use DATADIR as a typedef.