matrix_4x4_simd.h is not included by default

[nfrechette]

It appears that the SIMD specialization for the Matrix 4x4 isn't included by default which means it defaults to scalar code. This differs from the Vector types which include the SIMD specializations by default.

[lolanto]

BTW. Where is the definition of Simd4Union. I'll be appreciative if any one can tell me

[haroonq]

Looks like it was deleted here:

5b551fe#diff-a289be2a2ae231045093490e2a3f6e4dL36

FWIW, the definition was:

union Simd4fUnion {
simd4f simd;
float float_array[4];
};