dnl a macro to check for ability to create python extensions

dnl  AM_CHECK_PYTHON_HEADERS([ACTION-IF-POSSIBLE], [ACTION-IF-NOT-POSSIBLE])

dnl function also defines PYTHON_INCLUDES

AC_DEFUN([AM_CHECK_PYTHON_HEADERS],

[AC_REQUIRE([AM_PATH_PYTHON])

AC_ARG_VAR([PYTHON_CONFIG], [python-config executable])

AS_IF(

  [test "${PYTHON_CONFIG+set}" = set],

    [AC_MSG_NOTICE([PYTHON_CONFIG overridden to: $PYTHON_CONFIG])],

  [test -x "${PYTHON}-config"],

    [

      PYTHON_CONFIG="${PYTHON}-config"

      AC_MSG_NOTICE([Using \$PYTHON-config: $PYTHON_CONFIG])

    ],

  dnl else

    [

      AC_PATH_PROGS([PYTHON_CONFIG], [python${PYTHON_VERSION}-config python-config], [no])

      AS_IF([test "${PYTHON_CONFIG}" = "no"],

        [AC_MSG_ERROR([cannot find python${PYTHON_VERSION}-config or python-config in PATH])])

    ])

AC_ARG_VAR([PYTHON_INCLUDES], [CPPFLAGS for Python, overriding output of python2.x-config --includes, e.g. "-I/opt/misc/include/python2.7"])

if test "${PYTHON_INCLUDES+set}" = set; then

  AC_MSG_NOTICE([PYTHON_INCLUDES overridden to: $PYTHON_INCLUDES])

else

  dnl deduce PYTHON_INCLUDES

  AC_MSG_CHECKING(for Python headers using $PYTHON_CONFIG --includes)

  PYTHON_INCLUDES=`$PYTHON_CONFIG --includes`

  if test $? = 0; then

    AC_MSG_RESULT($PYTHON_INCLUDES)

  else

    AC_MSG_RESULT([failed, will try another way])

    py_prefix=`$PYTHON -c "import sys; print(sys.prefix)"`

    py_exec_prefix=`$PYTHON -c "import sys; print(sys.exec_prefix)"`

    AC_MSG_CHECKING(for Python headers in $py_prefix and $py_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}"

    fi

    AC_MSG_RESULT($PYTHON_INCLUDES)

  fi

fi

AC_MSG_CHECKING(whether those headers are sufficient)

AC_SUBST(PYTHON_INCLUDES)

dnl check if the headers exist:

save_CPPFLAGS="$CPPFLAGS"

CPPFLAGS="$CPPFLAGS $PYTHON_INCLUDES"

AC_TRY_CPP([#include <Python.h>],dnl

[AC_MSG_RESULT(yes)

$1],dnl

[AC_MSG_RESULT(no)

$2])

CPPFLAGS="$save_CPPFLAGS"

])