Fix `PLATFORM_GET_INC`

	On platforms where unaligned word access is not allowed, and if
	`sizeof(val)` and `sizeof(type)` differ:

	- `val` > `type`, `val` will be a garbage.
	- `val` < `type`, outside `val` will be clobbered.
	---
	 regexec.c | 2 +-
	 regint.h  | 9 ++++++++-
	 2 files changed, 9 insertions(+), 2 deletions(-)

note: ruby_3_1 is patched regint.h only