Ensure tests run using serial test harness (bug #914212), and do not
call ar directly (bug #722328)

--- a/configure.ac
+++ b/configure.ac
@@ -4,7 +4,7 @@
 # Initialization
 AC_PREREQ(2.59)
 AC_INIT(regex-markup, 0.10.0, oskar@osk.mine.nu)
-AM_INIT_AUTOMAKE
+AM_INIT_AUTOMAKE([serial-tests])
 AC_CONFIG_SRCDIR([src/remark.c])
 AC_CONFIG_HEADER([config.h])
 
@@ -19,6 +19,7 @@ AC_DEFINE_DIR(PKGDATADIR, datadir/$PACKAGE, [Directory where system-wide rule fi
 # Checks for programs.
 AC_PROG_CC
 AC_PROG_INSTALL
+AM_PROG_AR
 #AC_PROG_MAKE_SET
 AC_PROG_RANLIB
 AM_PROG_LEX