Fix little missed optimization.

[ginac.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index a932568ea99ff45f8b08ec14a5e819dbf476462b..6e4a4119d97cfadc8c7f59f09663d2e866b5bce5 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,7 @@ AS_IF([test -z "$YACCEXE" -a ! -f $srcdir/ginsh/ginsh_parser.hpp],
 
 dnl Switch to C++ language mode for the following libraries and headers.
 AC_LANG([C++])
+AX_CXX_COMPILE_STDCXX_11
 
 dnl Make sure all the necessary standard headers are installed on the system.
 GINAC_STD_CXX_HEADERS