[PATCH] marshal.c: properly freeze linked strings

	[Bug #21961]

This reverts commit 83637aea6ea726f7fc4c17e56ac60c289e2d98db.

	[Bug #21819] Data objects without members should also be frozen

	[Bug #21814] Fix negative bignum modulo

	If modulo is zero, do not  apply bias even if the divisor is zero.
	`BIGNUM_POSITIVE_P` is true even on bignum zero.

	[PATCH] Fix refinement modification of method visibility in superclass

	Previously, this didn't work correctly, resulting in a
	SystemStackError. This fixes the issue by finding the related
	superclass method entry, and updating the orig_me in the
	refinement method to point to the superclass method.

	Fixes [Bug #21446]

	[PATCH] Don't use non blocking pipes for RUBY_CRASH_REPORT

	[Bug #21703]

	RUBY_CRASH_REPORT does not work in some cases when shelling out on Linux.
	For example, given the following shell script dump.sh:

	    #!/usr/bin/env bash
	    cat > /tmp/crash

	And we see it fails like this:

	    $ RUBY_CRASH_REPORT="|dump.sh" ruby -rfiddle -e "Fiddle::Pointer.new(1, 10)[0]"
	    cat: -: Resource temporarily unavailable

Fixes [Bug #21266].

Backport of 9168cad4d63a5d281d443bde4edea6be213b0b25 to 3.3

Method#unbind clones the method entry, preserving its defined_class.
For methods mixed in via include/extend, defined_class is an ICLASS,
causing UnboundMethod#== to return false when comparing against the
same method obtained via Module#instance_method.

Resolve ICLASS defined_class in method_eq.

[Bug #21873]