Avoid compilation errors with MSVC option -fp:strict. * lib/floor.c: Use MSVC specific pragma fenv_access. * lib/ceil.c: Likewise. * lib/trunc.c: Likewise. * lib/round.c: Likewise. * lib/rint.c: Likewise. * lib/fma.c: Likewise. * lib/integer_length.c: Likewise. * m4/round.m4 (gl_FUNC_ROUND): Likewise. * m4/roundf.m4 (gl_FUNC_ROUNDF): Likewise. * tests/test-floor2.c: Likewise. * tests/test-floorf2.c: Likewise. * tests/test-ceil2.c: Likewise. * tests/test-ceilf2.c: Likewise. * tests/test-trunc2.c: Likewise. * tests/test-truncf2.c: Likewise. Reported by Michael Goffioul <michael.goffioul@gmail.com>.