c/float_asm: expand ignoring -Werror=uninitialized to gcc 12
c/float_asm: expand ignoring -Werror=uninitialized to gcc 12

On Fedora 37, gcc 12.0.1 also reports a use of an uninitialized value:

    float_asm.c: In function ‘invsqrt_f’:
    float_asm.c:225:9: error: ‘i’ is used uninitialized [-Werror=uninitialized]
      225 |     x = *(float *)&i;
          |         ^~~~~~~~~~~~
    float_asm.c:215:13: note: ‘i’ declared here
      215 |     int32_t i;
          |             ^
    float_asm.c: In function ‘invsqrt_d’:
    float_asm.c:245:9: error: ‘i’ is used uninitialized [-Werror=uninitialized]
      245 |     x = *(double *)&i;
          |         ^~~~~~~~~~~~~
    float_asm.c:236:13: note: ‘i’ declared here
      236 |     int64_t i;
          |             ^

Expand the check to ignore -Werror=uninitialized to gcc 12 too and
beyond.

fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared