configure: add pthreads, LIBVARNISHAPI_PREFIX, default prefix

configure.ac

@@ -20,6 +20,13 @@ if test "x$ac_cv_prog_cc_c99" = xno; then
 fi
 AC_PROG_CPP
 
+AX_PTHREAD(,[AC_MSG_ERROR([Could not configure pthreads support])])
+
+LIBS="$PTHREAD_LIBS $LIBS"
+CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+CC="$PTHREAD_CC"
+
+LT_INIT([disable-static])
 AC_PROG_INSTALL
 AC_PROG_LIBTOOL
 AC_PROG_MAKE_SET
@@ -56,6 +63,7 @@ AS_VAR_IF([$1], [""], [$5], [$4])dnl
 ])
 
 PKG_CHECK_MODULES([libvarnishapi], [varnishapi])
+PKG_CHECK_VAR([LIBVARNISHAPI_PREFIX], [varnishapi], [prefix])
 PKG_CHECK_VAR([LIBVARNISHAPI_DATAROOTDIR], [varnishapi], [datarootdir])
 PKG_CHECK_VAR([LIBVARNISHAPI_BINDIR], [varnishapi], [bindir])
 PKG_CHECK_VAR([LIBVARNISHAPI_SBINDIR], [varnishapi], [sbindir])
@@ -65,6 +73,9 @@ AC_SUBST([LIBVARNISHAPI_DATAROOTDIR])
 VARNISH_VMOD_INCLUDES
 VARNISH_VMOD_DIR
 VARNISH_VMODTOOL
+# inherit the prefix from Varnish.
+# acessing ac_ variable because AC_PREFIX_DEFAULT acts too early
+ac_default_prefix=$LIBVARNISHAPI_PREFIX
 
 AC_PATH_PROG([VARNISHTEST], [varnishtest], [],
     [$LIBVARNISHAPI_BINDIR:$LIBVARNISHAPI_SBINDIR:$PATH])