CONFIG_AMIGA is not available for the selected architecture x86.
Result is shown for architecture m68k

Amiga support

modulename: head.ko

configname: CONFIG_AMIGA

Linux Kernel Configuration
└─>Amiga support
In linux kernel since version 2.6.12 )
This option enables support for the Amiga series of computers. If
you plan to use this kernel on an Amiga, say Y here and browse the
material available in <a href="https://www.kernel.org/doc/Documentation/arch/m68k">Documentation/arch/m68k</a>; otherwise say N.
source code:
arch/m68k/kernel/
selects
CONFIG_MMU_MOTOROLA
CONFIG_LEGACY_TIMER_TICK