Enable the fiber ppc64 ELFv2 assembly on big-endian hosts as well (the
registers it saves are endian-neutral). Upstream simonfxr/fiber dc084920bc81,
not yet in the spicy snapshot bundled by zeek.

--- auxil/spicy/3rdparty/fiber/CMakeLists.txt.orig	2026-10-18 17:10:38 UTC
+++ auxil/spicy/3rdparty/fiber/CMakeLists.txt
@@ -82,7 +82,7 @@
   endif()
 elseif(CMU_OS_POSIX AND CMU_ARCH_RISCV)
   set(asm_sources src/fiber_asm_riscv_elf.S)
-elseif(CMU_OS_POSIX AND CMU_ARCH_PPC AND FIBER_BITS_64 AND CMU_LITTLE_ENDIAN)
+elseif(CMU_OS_POSIX AND CMU_ARCH_PPC AND FIBER_BITS_64)
   set(asm_sources src/fiber_asm_ppc64le_elf2.S)
 endif()