CONFIG_IRQ_GIC is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_IRQ_GIC (not configurable)

modulename: irq-gic.ko

configname: CONFIG_IRQ_GIC

Linux Kernel Configuration
└─>IRQ_GIC
In linux kernel since version 2.6.26 (release Date: 2008-07-13)  
source code:
arch/mips/kernel/irq-gic.c
selects
CONFIG_MIPS_CM

is selected by
CONFIG_CEVT_GIC