CONFIG_BOARD_ATSTK100X_CUSTOM is not available for thedefaultarchitecture x86.
Result is shown for architecture avr32

Non-default STK1002/STK1003/STK1004 jumper settings

configname: CONFIG_BOARD_ATSTK100X_CUSTOM

Linux Kernel Configuration
└─>Non-default STK1002/STK1003/STK1004 jumper settings
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
You will normally leave the jumpers on the CPU card at their
default settings. If you need to use certain peripherals,
you will need to change some of those jumpers.