ruby: Fix to work with autoconf 2.70

Drop a macro we don't need which was breaking with autoconf 2.70.

(From OE-Core rev: 995a0421ab39d62354e56f77eca10e2d176582d4)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/ruby/ruby/autoconf270.patch

@@ -0,0 +1,34 @@
+This macro breaks under autoconf 2.70. Since we don't worry abot darwin or
+openbsd builds, simply remove it.
+
+Upstream-Status: Pending
+RP - 2021/1/28
+
+Index: ruby-2.7.2/configure.ac
+===================================================================
+--- ruby-2.7.2.orig/configure.ac
++++ ruby-2.7.2/configure.ac
+@@ -170,23 +170,6 @@ dnl     orig_cxxflags="$cxxflags"
+ dnl     cxxflags="$cxxflags "'${optflags} ${debugflags} ${warnflags}'
+ dnl ])
+ 
+-AS_CASE(["$host_os:$build_os"],
+-[darwin*:darwin*], [
+-    AC_CHECK_TOOLS(CC, [clang gcc cc])
+-    # Following Apple deployed clang are broken
+-    # clang version 1.0 (http://llvm.org/svn/llvm-project/cfe/tags/Apple/clang-23 exported)
+-    # Apple clang version 2.0 (tags/Apple/clang-137) (based on LLVM 2.9svn)
+-    # Apple clang version 2.1 (tags/Apple/clang-163.7.1) (based on LLVM 3.0svn)
+-    AS_IF([! $CC -E -xc - <<SRC >/dev/null], [
+-	@%:@if defined __APPLE_CC__ && defined __clang_major__ && __clang_major__ < 3
+-	@%:@error premature clang
+-	@%:@endif
+-SRC
+-	AC_MSG_ERROR([clang version 3.0 or later is required])
+-    ])],
+-[openbsd*:openbsd*], [
+-    AC_CHECK_TOOLS(CC, [cc])
+-])
+ AS_IF([test x"${build}" != x"${host}"], [
+   AC_CHECK_TOOL(CC, gcc)
+ ])

meta/recipes-devtools/ruby/ruby_2.7.2.bb

@@ -7,6 +7,7 @@ SRC_URI += " \
            file://run-ptest \
            file://0001-Modify-shebang-of-libexec-y2racc-and-libexec-racc2y.patch \
            file://0001-template-Makefile.in-do-not-write-host-cross-cc-item.patch \
+           file://autoconf270.patch \
            "
 
 SRC_URI[md5sum] = "2d4a28dcfa38352a627a597f6057c465"