type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]

[strk]

Recently introduced:

g_serialized.c: In function ‘gserialized_cmp’:
g_serialized.c:308:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
   *(uint32_t*)(g1->data) == POINTTYPE &&
   ^
g_serialized.c:309:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
   *(uint32_t*)(g2->data) == POINTTYPE &&
   ^

strict aliasing rules are there so you don't assume it is safe to cast to pointers to structors of different alignemnt constraints.

[komzpa]

fix: ​https://github.com/postgis/postgis/pull/161

[strk]

In 15976:

Fix GCC warnings

Obey const pointer in autofix logic.
Move ring closing logic to ptarray_to_GEOSCoordSeq.
Fix memory access.

Patch by Darafei Praliaskouski <me@…>

Fixes #3900

[robe]

This was marked for 2.4.1 release but was not back-ported to 2.4.1. I've change the milestone to 2.5.0. If this is wrong, fix in 2.4.1 and change milestone back.

[dbaston]

Is there a reason not to backport this? I'm still getting this error when building the 2.4 branch.