Draft: */php{7,8,81}: fix x86 FPU, remove glibc LFS defs (fixes #11645)

instead of mangling the fpu control, just force php to use sse. this means that floating-point operations in php on pre-sse x86 processors will crash instead of silently producing incorrect results. this is most likely a negligible proportion of users; if they want to have wrong fpu results instead of crashing, then they can recompile php.