CONFIG_MATHEMU is not available for the selected architecture x86.
Result is shown for architecture alpha

Kernel FP software completion

modulename: math-emu.ko

configname: CONFIG_MATHEMU

Linux Kernel Configuration
└─>Kernel FP software completion
In linux kernel since version 2.6.12 )
This option is required for IEEE compliant floating point arithmetic
on the Alpha. The only time you would ever not say Y is to say M in
order to debug the code. Say Y unless you know what you are doing.
source code: