Disable noexcept-type warning of g++-7

configure.ac

@@ -243,6 +243,9 @@ if test "x$werror" != "xno"; then
     #AX_CHECK_COMPILE_FLAG([-Werror], [CXXFLAGS="$CXXFLAGS -Werror"])
     AX_CHECK_COMPILE_FLAG([-Wformat-security], [CXXFLAGS="$CXXFLAGS -Wformat-security"])
     AX_CHECK_COMPILE_FLAG([-Wsometimes-uninitialized], [CXXFLAGS="$CXXFLAGS -Wsometimes-uninitialized"])
+    # Disable noexcept-type warning of g++-7.  This is not harmful as
+    # long as all source files are compiled with the same compiler.
+    AX_CHECK_COMPILE_FLAG([-Wno-noexcept-type], [CXXFLAGS="$CXXFLAGS -Wno-noexcept-type"])
     AC_LANG_POP()
 fi