merge revision(s) 09295ea796900fb7b05d29e93364090e21598566: [Backport #19543]

	IO::Buffer#resize: Free internal buffer if new size is zero (#7569)

	`#resize(0)` on an IO::Buffer with internal buffer allocated will
	result in calling `realloc(data->base, 0)`. The behavior of `realloc`
	with size = 0 is implementation-defined (glibc frees the object
	and returns NULL, while BSDs return an inaccessible object). And
	thus such usage is deprecated in standard C (upcoming C23 will make it
	UB).

	To avoid this problem, just `free`s the memory when the new size is zero.
	---
	 io_buffer.c                 |  5 +++++
	 test/ruby/test_io_buffer.rb | 18 ++++++++++++++++++
	 2 files changed, 23 insertions(+)

0 files changed, 0 insertions, 0 deletions