CONFIG_MACH_EUKREA_CPUIMX51SD is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Support Eukrea CPUIMX51SD module

modulename: board-cpuimx51sd.ko

and/or

mach-cpuimx51sd.ko

configname: CONFIG_MACH_EUKREA_CPUIMX51SD

Linux Kernel Configuration
└─>Support Eukrea CPUIMX51SD module
In linux kernel since version 2.6.37 (release Date: 2011-01-04)  
Include support for Eukrea CPUIMX51SD platform. This includes
specific configurations for the module and its peripherals.

source code:
arch/arm/mach-mx5/board-cpuimx51sd.c