fpending: Port to native Windows with MSVC. * lib/fpending.c: Include stdio-impl.h. (__fpending): Include all known implementations. Err out if it's not ported. * m4/fpending.m4 (gl_PREREQ_FPENDING): Remove macro. * modules/fpending (Files): Add lib/stdio-impl.h. (configure.ac): Don't invoke gl_PREREQ_FPENDING.