# patch-libwebp-simd.cmake — portable, idempotent FetchContent patch for libwebp.
#
# libwebp's cmake/cpu.cmake compiles its scalar *reference* DSP files with the
# SSE-disable flags "-mno-sse4.1;-mno-sse2" whenever it can't positively detect
# SSE support. Under a macOS *universal* build (-arch arm64;x86_64) the per-arch
# SSE flag probe fails (a flag valid for x86_64 is invalid for arm64), so those
# disable flags get applied to the x86_64 slice. clang gates the _Float16 type on
# SSE2 for x86_64, and the macOS 15+/26 SDK's <math.h> declares _Float16 math
# functions unconditionally — so any TU including <math.h> fails to compile with
# "_Float16 is not supported on this target".
#
# SSE2 is part of the x86_64 baseline ABI, so disabling it on the reference files
# is unnecessary on every platform we target. Blanking the SSE entries (indices
# must stay aligned with WEBP_SIMD_FLAGS) fixes the universal build and is a no-op
# for single-arch Linux/Windows/x86_64 builds. Idempotent: re-running is a no-op.
if(NOT DEFINED CPU_CMAKE OR NOT EXISTS "${CPU_CMAKE}")
    message(FATAL_ERROR "patch-libwebp-simd: cpu.cmake not found at '${CPU_CMAKE}'")
endif()

file(READ "${CPU_CMAKE}" _contents)
string(REPLACE
    "set(SIMD_DISABLE_FLAGS \"-mno-sse4.1;-mno-sse2;;-mno-dspr2;;-mno-msa\")"
    "set(SIMD_DISABLE_FLAGS \";;;-mno-dspr2;;-mno-msa\")"
    _patched "${_contents}")

if(_patched STREQUAL _contents)
    message(STATUS "patch-libwebp-simd: no change (already patched or pattern absent)")
else()
    file(WRITE "${CPU_CMAKE}" "${_patched}")
    message(STATUS "patch-libwebp-simd: neutralized x86 SSE-disable flags in cpu.cmake")
endif()