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

CONFIG_ARCH_SPARSEMEM_ENABLE (not configurable)

configname: CONFIG_ARCH_SPARSEMEM_ENABLE

Linux Kernel Configuration
└─>System Type and features
└─>ARCH_SPARSEMEM_ENABLE
In linux kernel since version 2.6.13 (release Date: 2005-08-28)