REGRESSION(278410@main): Fails to build with clang: error: _Float16 i…

…s not supported on this target

https://bugs.webkit.org/show_bug.cgi?id=274086

Unreviewed build fix for s390x, and also i386 with SSE2 disabled.

I've submitted these changes to upstream SIMDE to ensure they hopefully
don't get lost when rebasing:

simd-everywhere/simde#1182

* Source/WTF/wtf/simde/arm/neon.h:

Canonical link: https://commits.webkit.org/278821@main

Source/WTF/wtf/simde/arm/neon.h

@@ -8778,15 +8778,13 @@ SIMDE_BEGIN_DECLS_
 #if !defined(SIMDE_FLOAT16_API)
   #if defined(__ARM_FP16_FORMAT_IEEE) && (defined(SIMDE_ARM_NEON_FP16) || defined(__ARM_FP16_ARGS))
     #define SIMDE_FLOAT16_API SIMDE_FLOAT16_API_FP16
-  #elif !defined(__EMSCRIPTEN__) && !(defined(__clang__) && defined(SIMDE_ARCH_POWER)) && \
+  #elif !defined(__EMSCRIPTEN__) && \
     !(defined(HEDLEY_MSVC_VERSION) && defined(__clang__)) && \
-    !(defined(SIMDE_ARCH_MIPS) && defined(__clang__)) && \
     !(defined(__clang__) && defined(SIMDE_ARCH_RISCV64)) && ( \
       defined(SIMDE_X86_AVX512FP16_NATIVE) || \
       (defined(SIMDE_ARCH_X86_SSE2) && HEDLEY_GCC_VERSION_CHECK(12,0,0)) || \
       (defined(SIMDE_ARCH_AARCH64) && HEDLEY_GCC_VERSION_CHECK(7,0,0) && !defined(__cplusplus)) || \
-      ((defined(SIMDE_ARCH_X86) || defined(SIMDE_ARCH_AMD64)) && SIMDE_DETECT_CLANG_VERSION_CHECK(15,0,0)) || \
-      (!(defined(SIMDE_ARCH_X86) || defined(SIMDE_ARCH_AMD64)) && SIMDE_DETECT_CLANG_VERSION_CHECK(6,0,0))) || \
+      ((defined(SIMDE_ARCH_X86_SSE2) || defined(SIMDE_ARCH_AMD64)) && SIMDE_DETECT_CLANG_VERSION_CHECK(15,0,0))) || \
       defined(SIMDE_ARCH_RISCV_ZVFH)
     /* We haven't found a better way to detect this.  It seems like defining
     * __STDC_WANT_IEC_60559_TYPES_EXT__, then including float.h, then