Warn when we fail to trace and SELinux boolean deny_ptrace is in effect
diff --git a/configure.ac b/configure.ac
index 7fcfda5..42d6158 100644
--- a/configure.ac
+++ b/configure.ac
@@ -82,6 +82,11 @@
 AC_SUBST(libsupcxx_LIBS)
 
 
+dnl Check security_get_boolean_active availability.
+AC_CHECK_HEADERS(selinux/selinux.h)
+AC_CHECK_LIB(selinux, security_get_boolean_active)
+
+
 # HAVE_LIBUNWIND
 AC_ARG_WITH(libunwind,
   AS_HELP_STRING([--with-libunwind], [Use libunwind frame unwinding support]),