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Diffstat (limited to 'dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m4')
-rw-r--r--dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m415
1 files changed, 13 insertions, 2 deletions
diff --git a/dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m4 b/dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m4
index 43087b2e68..9413da624d 100644
--- a/dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m4
+++ b/dviware/dvisvgm/m4/ax_cxx_compile_stdcxx.m4
@@ -16,7 +16,7 @@
# The second argument, if specified, indicates whether you insist on an
# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
# -std=c++11). If neither is specified, you get whatever works, with
-# preference for an extended mode.
+# preference for no added switch, and then for an extended mode.
#
# The third argument, if specified 'mandatory' or if left unspecified,
# indicates that baseline support for the specified C++ standard is
@@ -35,13 +35,14 @@
# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
# Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
# Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
+# Copyright (c) 2020 Jason Merrill <jason@redhat.com>
#
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty provided the copyright notice
# and this notice are preserved. This file is offered as-is, without any
# warranty.
-#serial 11
+#serial 12
dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
dnl (serial version number 13).
@@ -62,6 +63,16 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
AC_LANG_PUSH([C++])dnl
ac_success=no
+ m4_if([$2], [], [dnl
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+ ax_cv_cxx_compile_cxx$1,
+ [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [ax_cv_cxx_compile_cxx$1=yes],
+ [ax_cv_cxx_compile_cxx$1=no])])
+ if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+ ac_success=yes
+ fi])
+
m4_if([$2], [noext], [], [dnl
if test x$ac_success = xno; then
for alternative in ${ax_cxx_compile_alternatives}; do