CONFIG_NIOS2_FPU_SUPPORT is not available for thedefaultarchitecture x86.
Result is shown for architecture nios2
Custom floating point instr support
configname: CONFIG_NIOS2_FPU_SUPPORT
Linux Kernel Configuration
└─>Platform options
└─>Custom floating point instr support
In linux kernel since version 3.19 (release Date: 2015-02-08)
Enables the -mcustom-fpu-cfg=60-1 compiler flag.