arm: fix compilation warnings
* configure.ac: Define SIZEOF_LONG.
* signal.c (sys_rt_sigaction) [SUPPORTED_PERSONALITIES > 1]: Help
compiler to optimize out unreachable code that is not expected to work
on platforms where sizeof(long) <= 4.
diff --git a/configure.ac b/configure.ac
index ee9b8e8..f5118ca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -251,6 +251,8 @@
AC_DEFINE([HAVE_BLKGETSIZE64], [1], [Define to 1 if you have BLKGETSIZE64.])
fi)
+AC_CHECK_SIZEOF([long])
+
AC_PATH_PROG([PERL], [perl])
AC_CONFIG_FILES([Makefile tests/Makefile])