CONFIG_MACH_OVERO is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_OVERO.
Result is shown for kernelversion 6.5.1

Gumstix Overo board

modulename: board-overo.ko

configname: CONFIG_MACH_OVERO

Linux Kernel Configuration
└─>TI OMAP2/3/4 Specific Features
└─>Gumstix Overo board
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  
source code: