-# Determine CFLAGS for gthread.
-# FIXME: the current implementation is dependent on the 'r' variable
-# passed down from the top level
-AC_CACHE_CHECK([for gthread cflags],objc_cv_gthread_flags,
-[if test -f "$r"/gcc/Makefile
-then
- objc_cv_gthread_flags=`grep \^GTHREAD_FLAGS "$r"/gcc/Makefile | awk -F= '{ print $2 }'`
+AC_MSG_CHECKING([for thread model used by GCC])
+target_thread_file=`$CC -v 2>&1 | sed -n 's/^Thread model: //p'`
+AC_MSG_RESULT([$target_thread_file])
+
+if test $target_thread_file != single; then
+ AC_DEFINE(HAVE_GTHR_DEFAULT, 1,
+ [Define if the compiler has a thread header that is non single.])
+fi
+
+# Check if we have thread-local storage
+GCC_CHECK_TLS
+
+AC_MSG_CHECKING([for exception model to use])
+AC_LANG_PUSH(C)
+AC_ARG_ENABLE(sjlj-exceptions,
+ AS_HELP_STRING([--enable-sjlj-exceptions],
+ [force use of builtin_setjmp for exceptions]),
+[:],
+[dnl Botheration. Now we've got to detect the exception model.
+dnl Link tests against libgcc.a are problematic since -- at least
+dnl as of this writing -- we've not been given proper -L bits for
+dnl single-tree newlib and libgloss.
+dnl
+dnl This is what AC_TRY_COMPILE would do if it didn't delete the
+dnl conftest files before we got a change to grep them first.
+cat > conftest.$ac_ext << EOF
+[#]line __oline__ "configure"
+@interface Frob
+@end
+@implementation Frob
+@end
+int proc();
+int foo()
+{
+ @try {
+ return proc();
+ }
+ @catch (Frob* ex) {
+ return 0;
+ }
+}
+EOF
+old_CFLAGS="$CFLAGS"
+dnl work around that we don't have Objective-C support in autoconf
+CFLAGS="-x objective-c -fgnu-runtime -fobjc-exceptions -S"
+if AC_TRY_EVAL(ac_compile); then
+ if grep _Unwind_SjLj_Resume conftest.s >/dev/null 2>&1 ; then
+ enable_sjlj_exceptions=yes
+ elif grep _Unwind_Resume conftest.s >/dev/null 2>&1 ; then
+ enable_sjlj_exceptions=no
+ fi
+fi
+CFLAGS="$old_CFLAGS"
+rm -f conftest*])
+if test x$enable_sjlj_exceptions = xyes; then
+ AC_DEFINE(SJLJ_EXCEPTIONS, 1,
+ [Define if the compiler is configured for setjmp/longjmp exceptions.])
+ ac_exception_model_name=sjlj
+elif test x$enable_sjlj_exceptions = xno; then
+ ac_exception_model_name="call frame"