Do not build the little-endian-only VSX hash kernel on big-endian.

--- src/CMakeLists.txt.orig	2026-09-14 17:24:06 UTC
+++ src/CMakeLists.txt
@@ -473,9 +473,11 @@
     target_sources(zeek_hhash_obj PRIVATE ${hhash_dir}/hh_neon.cc)
     list(APPEND hhash_sources ${hhash_dir}/hh_neon.cc)
 elseif (${COMPILER_ARCHITECTURE} STREQUAL "power")
+    if (CMAKE_CXX_BYTE_ORDER STREQUAL "LITTLE_ENDIAN")
     target_sources(zeek_hhash_obj PRIVATE ${hhash_dir}/hh_vsx.cc)
     set_source_files_properties(${hhash_dir}/hh_vsx.cc PROPERTIES COMPILE_FLAGS -mvsx)
     list(APPEND hhash_sources ${hhash_dir}/hh_vsx.cc)
+    endif ()
 elseif (${COMPILER_ARCHITECTURE} STREQUAL "x86_64")
     target_sources(zeek_hhash_obj PRIVATE ${hhash_dir}/hh_avx2.cc ${hhash_dir}/hh_sse41.cc)
     if (MSVC)