Bump the required BASERUBY version to 2.7 (#9566)

[[Misc #16671]](https://bugs.ruby-lang.org/issues/16671)

.github/workflows/baseruby.yml

@@ -50,9 +50,7 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - ruby-2.5
-#         - ruby-2.6
-#         - ruby-2.7
+          - ruby-2.7
           - ruby-3.0
           - ruby-3.1
           - ruby-3.2

.github/workflows/mingw.yml

@@ -59,7 +59,7 @@ jobs:
         include:
           # To mitigate flakiness of MinGW CI, we test only one runtime that newer MSYS2 uses.
           - msystem: 'UCRT64'
-            base_ruby: head
+            baseruby: '2.7'
             test_task: 'check'
             test-all-opts: '--name=!/TestObjSpace#test_reachable_objects_during_iteration/'
       fail-fast: false
@@ -76,7 +76,7 @@ jobs:
       - name: Set up Ruby & MSYS2
         uses: ruby/setup-ruby@360dc864d5da99d54fcb8e9148c14a84b90d3e88 # v1.165.1
         with:
-          ruby-version: ${{ matrix.base_ruby }}
+          ruby-version: ${{ matrix.baseruby }}
 
       - name: where check
         run: |

.github/workflows/windows.yml

@@ -133,6 +133,7 @@ jobs:
           builddir: build
 
       - name: setup env
+        # Available Ruby versions: https://github.com/actions/runner-images/blob/main/images/windows/Windows2019-Readme.md#ruby
         # %TEMP% is inconsistent with %TMP% and test-all expects they are consistent.
         # https://github.com/actions/virtual-environments/issues/712#issuecomment-613004302
         run: |
@@ -146,10 +147,14 @@ jobs:
           set TEMP=%USERPROFILE%\AppData\Local\Temp
           set MAKEFLAGS=l
           set /a TEST_JOBS=(15 * %NUMBER_OF_PROCESSORS% / 10) > nul
+          set PATH=C:\hostedtoolcache\windows\Ruby\2.7.8\x64\bin;%PATH%
           set | C:\msys64\usr\bin\sort > new.env
           C:\msys64\usr\bin\comm -13 old.env new.env >> %GITHUB_ENV%
           del *.env
 
+      - name: baseruby version
+        run: ruby -v
+
       - name: compiler version
         run: cl
 

configure.ac

@@ -75,8 +75,8 @@ AC_ARG_WITH(baseruby,
 	[
 		AC_PATH_PROG([BASERUBY], [ruby], [false])
 	])
-# BASERUBY must be >= 2.5.0. Note that `"2.5.0" > "2.5"` is true.
-AS_IF([test "$HAVE_BASERUBY" != no -a "`RUBYOPT=- $BASERUBY --disable=gems -e 'print 42 if RUBY_VERSION > "2.5"' 2>/dev/null`" = 42], [
+# BASERUBY must be >= 2.7.0. Note that `"2.7.0" > "2.7"` is true.
+AS_IF([test "$HAVE_BASERUBY" != no -a "`RUBYOPT=- $BASERUBY --disable=gems -e 'print 42 if RUBY_VERSION > "2.7"' 2>/dev/null`" = 42], [
     AS_CASE(["$build_os"], [mingw*], [
         # Can MSys shell run a command with a drive letter?
         RUBYOPT=- `cygpath -ma "$BASERUBY"` --disable=gems -e exit 2>/dev/null || HAVE_BASERUBY=no