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-rw-r--r--config/tls.m421
1 files changed, 21 insertions, 0 deletions
diff --git a/config/tls.m4 b/config/tls.m4
new file mode 100644
index 0000000..5cbb685
--- /dev/null
+++ b/config/tls.m4
@@ -0,0 +1,21 @@
+dnl Check whether the target supports TLS.
+AC_DEFUN([GCC_CHECK_TLS], [
+ GCC_ENABLE(tls, yes, [Use thread-local storage])
+ AC_CACHE_CHECK([whether the target supports thread-local storage],
+ have_tls, [
+ AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+ [dnl If the test case passed with dynamic linking, try again with
+ dnl static linking. This fails at least with some older Red Hat
+ dnl releases.
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="-static $LDFLAGS"
+ AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+ [have_tls=yes], [have_tls=no], [])
+ LDFLAGS="$save_LDFLAGS"],
+ [have_tls=no],
+ [AC_COMPILE_IFELSE([__thread int foo;], [have_tls=yes], [have_tls=no])]
+ )])
+ if test "$enable_tls $have_tls" = "yes yes"; then
+ AC_DEFINE(HAVE_TLS, 1,
+ [Define to 1 if the target supports thread-local storage.])
+ fi])