configure: Fix floating point conformance ith icl.

Reviewed-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -3359,9 +3359,9 @@ probe_cc(){
         _ld_path='-libpath:'
         # -Qdiag-error to make icl error when seeing certain unknown arguments
         _flags='-nologo -Qdiag-error:4044,10157'
-        # -Qvec- -Qsimd- to prevent miscompilation, -GS for consistency
+        # -Qvec- -Qsimd- to prevent miscompilation, -GS, fp:precise for consistency
         # with MSVC which enables it by default.
-        _cflags='-D_USE_MATH_DEFINES -FIstdlib.h -Dstrtoll=_strtoi64 -Qms0 -Qvec- -Qsimd- -GS'
+        _cflags='-D_USE_MATH_DEFINES -FIstdlib.h -Dstrtoll=_strtoi64 -Qms0 -Qvec- -Qsimd- -GS -fp:precise'
         if [ $pfx = hostcc ]; then
             append _cflags -Dsnprintf=_snprintf
         fi