acinlude.m4: python3 compatible print

Python3 and python2 compatible print call in configure script.

acinclude.m4

@@ -483,8 +483,8 @@ AC_DEFUN([AM_CHECK_PYTHON_HEADERS],
 [AC_REQUIRE([AM_PATH_PYTHON])
 AC_MSG_CHECKING(for headers required to compile python extensions)
 dnl deduce PYTHON_INCLUDES
-py_prefix=`$PYTHON -c "import sys; print sys.prefix"`
-py_exec_prefix=`$PYTHON -c "import sys; print sys.exec_prefix"`
+py_prefix=`$PYTHON -c "import sys; print(sys.prefix)"`
+py_exec_prefix=`$PYTHON -c "import sys; print(sys.exec_prefix)"`
 PYTHON_INCLUDES="-I${py_prefix}/include/python${PYTHON_VERSION}"
 if test "$py_prefix" != "$py_exec_prefix"; then
   PYTHON_INCLUDES="$PYTHON_INCLUDES -I${py_exec_prefix}/include/python${PYTHON_VERSION}"