This reverts commit 56c311aa0b20dee13ab43309ae3386f57f8cb797.

Separate the directly from the customized test-unit, since it may not
work with bundled gems.

	Clear runtime dependencies if default gems is specified.

	The current build system uses runtime dependencies from only
	`.bundle` directory. We shouldn't install runtime dependencies
	from rubygems.org when `make test-bundled-gems` is invoked.

	Fixed dependencies list format

	Re-use strscan with ruby repo

This reverts commit ec30266267b2a063089b8ce7967203bcbadbdf4e.

This reverts commit dc4ca25e0a01e072ba3cf1fc47612aff72c980af.

	ci: Test whether GMP is working in compilers.yml (#10875)

	Avoid reoccurence of [Bug #20515]

	Requires https://github.com/ruby/ruby/pull/10876 since 18eaf0be905e3e251423b42d6f4e56b7cae1bc3b

	bug: https://bugs.ruby-lang.org/issues/20515

	RUBY_CHECK_HEADER didn't define HAVE_{header-file} (#10876)

	--with-gmp is not working at all because HAVE_GMP_H
	was missing since 18eaf0be90. [Bug #20515]

	bug: https://bugs.ruby-lang.org/issues/20515
	follow-up: https://bugs.ruby-lang.org/issues/20494
	follow-up: 18eaf0be905e3e251423b42d6f4e56b7cae1bc3b
	follow-up: https://github.com/ruby/ruby/pull/10805

	test_bignum: defined? returns String (#10880)
	MIME-Version: 1.0
	Content-Type: text/plain; charset=UTF-8
	Content-Transfer-Encoding: 8bit

	didn't verify the test is working properly due to mistaken auto-merge… [Bug #20515]

	bug: https://bugs.ruby-lang.org/issues/20515
	follow-up: 22e4eeda6561693367fc7a00b92b90f46b09cabd
	follow-up: https://github.com/ruby/ruby/pull/10875

	[Bug #20494] Search non-default directories for GMP

	Co-Authored-by: lish82 (Hiroki Katagiri)

This reverts commit 0de1ff12973ffc04bc9a8b0799e963922986d1eb.

	Clear runtime dependencies if default gems is specified.

	The current build system uses runtime dependencies from only
	`.bundle` directory. We shouldn't install runtime dependencies
	from rubygems.org when `make test-bundled-gems` is invoked.

	Fixed dependencies list format

	Re-use strscan with ruby repo

	[Bug #19967] Reset `LIBPATHENV` env after started

	Not to affect other tools invoked as child processes.
	---
	 common.mk            | 3 ++-
	 template/Makefile.in | 3 +++
	 template/fake.rb.in  | 3 +++
	 tool/fake.rb         | 8 ++++++++
	 4 files changed, 16 insertions(+), 1 deletion(-)

	[Bug #19967] Revert "configure.ac: LIBPATHENV on macOS"

	This reverts commit 1961c786aab243b3eb60e7238224e87975d88056.  These
	environment variables should no longer propagate to child processes.
	---
	 configure.ac | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

	[Bug #19967] Delete real path

	---
	 tool/fake.rb | 3 ++-
	 1 file changed, 2 insertions(+), 1 deletion(-)

	[Bug #19967] Ignore library before build

	---
	 tool/fake.rb | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)