adjusted the strerror_r test more, use _REENTRANT instead of _THREAD_SAFE

dnl

AC_DEFUN([CURL_CHECK_STRERROR_R],

[

  dnl determine of strerror_r is present

  AC_CHECK_FUNC(strerror_r,

    strerror_r="yes",

    [

  AC_CHECK_FUNCS(strerror_r)

  if test "x$ac_cv_func_strerror_r" = "xyes"; then

    AC_MSG_CHECKING(whether strerror_r is declared)

    AC_EGREP_CPP(strerror_r,[

#include <string.h>],[

      strerror_r="yes"

      AC_MSG_RESULT(yes)],[

      AC_MSG_RESULT(no)

      AC_MSG_CHECKING(whether strerror_r with -D_THREAD_SAFE is declared)

      AC_MSG_CHECKING(whether strerror_r with -D_REENTRANT is declared)

      AC_EGREP_CPP(strerror_r,[

#define _THREAD_SAFE

#define _REENTRANT

#include <string.h>],[

        strerror_r="yes"

	CPPFLAGS="-D_THREAD_SAFE $CPPFLAGS"

	CPPFLAGS="-D_REENTRANT $CPPFLAGS"

	AC_MSG_RESULT(yes)],

	AC_MSG_RESULT(no))])])

  if test "x$strerror_r" = "xyes"; then

    dnl check if strerror_r is properly declared in the headers

    AC_CHECK_DECL(strerror_r, ,

	AC_MSG_RESULT(no)

        AC_DEFINE(HAVE_NO_STRERROR_R_DECL, 1, [we have no strerror_r() proto])

,

[#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

])

       ) dnl with _THREAD_SAFE

    ]) dnl plain cpp for it

    dnl determine if this strerror_r() is glibc or POSIX

    AC_MSG_CHECKING([for a glibc strerror_r API])