js: additional check for _mm_mask_blend_epi32
Travis is now sometimes running on machines with support, which
is resulting is some compile-time errors for versions of clang which
don't support _mm_mask_blend_epi32.  This just checks for the builtin
used to implement _mm_mask_bleng_epi32 on clang before using it,
hopefully that's sufficient.
@@ -400,7 +400,8 @@ simde_em_int32x4_select (simde_em_bool32x4 selector, simde_em_int32x4 a, simde_e
#if defined(SIMDE_EM_NATIVE)
return SIMDE_EM_INT32X4_C(emscripten_int32x4_select(selector.n, a.n, b.n));
#elif defined(SIMDE_EM_SSE2)
- #if defined(__AVX512VL__)
+ #if defined(__AVX512VL__) && \
+ (!defined(__clang__) || HEDLEY_HAS_BUILTIN(__builtin_ia32_blendmd_128_mask))
return SIMDE_EM_INT32X4_SSE_C(_mm_mask_blend_epi32(selector.n, b.n, a.n));
#else
/* TODO: check if this is faster than the portable version */
