[PATCH] _AC_PROG_CXX_STDCXX_EDITION_TRY: fix typo in variable name

[Emanuele Giaquinta]

The typo causes "ac_prog_cxx_stdcxx" to be always set to "cxx11",
regardless of whether the C++ compiler supports C++11.
---
 lib/autoconf/c.m4 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 9f881f0b..47434c89 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -2749,8 +2749,8 @@ AC_DEFUN([_AC_PROG_CXX_STDCXX_EDITION_TRY],
 [AC_REQUIRE([_AC_CXX_CXX$1_TEST_PROGRAM])]dnl
 [AS_IF([test x$ac_prog_cxx_stdcxx = xno],
 [AC_MSG_CHECKING([for $CXX option to enable C++$1 features])
-AC_CACHE_VAL(ac_cv_prog_cxx_$1,
-[ac_cv_prog_cxx_$1=no
+AC_CACHE_VAL(ac_cv_prog_cxx_cxx$1,
+[ac_cv_prog_cxx_cxx$1=no
 ac_save_CXX=$CXX
 AC_LANG_CONFTEST([AC_LANG_DEFINES_PROVIDED][$][ac_cxx_conftest_cxx$1_program])
 for ac_arg in '' m4_normalize(m4_defn([_AC_CXX_CXX$1_OPTIONS]))
-- 
2.24.3 (Apple Git-128)