AC_CHECK_DECL([exp2l], , [HAVE_DECL_EXP2L=0], [[#include <math.h>]])
m4_ifdef([gl_FUNC_EXP2L_IEEE], [
if test $gl_exp2l_required = ieee && test $REPLACE_EXP2L = 0; then
AC_CHECK_DECL([exp2l], , [HAVE_DECL_EXP2L=0], [[#include <math.h>]])
m4_ifdef([gl_FUNC_EXP2L_IEEE], [
if test $gl_exp2l_required = ieee && test $REPLACE_EXP2L = 0; then