merge revision(s) 22e4eeda6561693367fc7a00b92b90f46b09cabd, 1ab7c412d2e3880a7ad233c32e93961888f8145c, fd549b229b0822198ddc847703194263a2186ed1: [Backport #20515]

	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

4 files changed, 10 insertions, 3 deletions

diff --git a/.github/workflows/compilers.yml b/.github/workflows/compilers.yml
index 731bda1cda..431a839e61 100644
--- a/.github/workflows/compilers.yml
+++ b/.github/workflows/compilers.yml
@@ -1,3 +1,4 @@
+# Some tests depending on this name 'Compilations' via $GITHUB_WORKFLOW. Make sure to update such tests when renaming this workflow.
 name: Compilations
 
 on:
@@ -147,7 +148,7 @@ jobs:
           - { name: '-O0', env: { optflags: '-O0 -march=x86-64 -mtune=generic' } }
 #         - { name: '-O3', env: { optflags: '-O3 -march=x86-64 -mtune=generic' }, check: true }
 
-          - { name: gmp,                  env: { append_configure: '--with-gmp' } }
+          - { name: gmp,                  env: { append_configure: '--with-gmp' }, check: true }
           - { name: jemalloc,             env: { append_configure: '--with-jemalloc' } }
           - { name: valgrind,             env: { append_configure: '--with-valgrind' } }
           - { name: 'coroutine=ucontext', env: { append_configure: '--with-coroutine=ucontext' } }
diff --git a/test/ruby/test_bignum.rb b/test/ruby/test_bignum.rb
index 065a944853..1b705b02a8 100644
--- a/test/ruby/test_bignum.rb
+++ b/test/ruby/test_bignum.rb
@@ -821,5 +821,11 @@ class TestBignum < Test::Unit::TestCase
     assert_nil(T1024P.infinite?)
     assert_nil((-T1024P).infinite?)
   end
+
+  def test_gmp_version
+    if RbConfig::CONFIG.fetch('configure_args').include?("'--with-gmp'")
+      assert_kind_of(String, Integer::GMP_VERSION)
+    end
+  end if ENV['GITHUB_WORKFLOW'] == 'Compilations'
 end
 end
diff --git a/tool/m4/ruby_check_header.m4 b/tool/m4/ruby_check_header.m4
index 171455549e..6fec9d16c5 100644
--- a/tool/m4/ruby_check_header.m4
+++ b/tool/m4/ruby_check_header.m4
@@ -3,6 +3,6 @@ AC_DEFUN([RUBY_CHECK_HEADER],
     [# RUBY_CHECK_HEADER($@)
     save_CPPFLAGS="$CPPFLAGS"
     CPPFLAGS="$CPPFLAGS m4_if([$5], [], [$INCFLAGS], [$5])"
-    AC_CHECK_HEADER([$1], [$2], [$3], [$4])
+    AC_CHECK_HEADERS([$1], [$2], [$3], [$4])
     CPPFLAGS="$save_CPPFLAGS"
     unset save_CPPFLAGS])
diff --git a/version.h b/version.h
index fb7fa3124c..8b34b41fd9 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 4
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 177
+#define RUBY_PATCHLEVEL 178
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"