diff --git a/configure.ac b/configure.ac
index f4073d0..5fe652e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -301,13 +301,12 @@ AC_ARG_WITH(
 	[with_crypto_library="openssl"]
 )
 
-AC_ARG_WITH(
-	[plugindir],
-	[AS_HELP_STRING([--with-plugindir], [plugin directory @<:@default=LIBDIR/openvpn@:>@])],
-	,
-	[with_plugindir="\$(libdir)/openvpn/plugins"]
-)
-
+AC_ARG_VAR([PLUGINDIR], [Path of plug-in directory @<:@default=LIBDIR/openvpn/plugins@:>@])
+if test -n "${PLUGINDIR}"; then
+	plugindir="${PLUGINDIR}"
+else
+	plugindir="\${libdir}/openvpn/plugins"
+fi
 
 AC_DEFINE_UNQUOTED([TARGET_ALIAS], ["${host}"], [A string representing our host])
 case "$host" in
@@ -1245,7 +1244,6 @@ AM_CONDITIONAL([ENABLE_PLUGIN_AUTH_PAM], [test "${enable_plugin_auth_pam}" = "ye
 AM_CONDITIONAL([ENABLE_PLUGIN_DOWN_ROOT], [test "${enable_plugin_down_root}" = "yes"])
 AM_CONDITIONAL([ENABLE_CRYPTO], [test "${enable_crypto}" = "yes"])
 
-plugindir="${with_plugindir}"
 sampledir="\$(docdir)/sample"
 AC_SUBST([plugindir])
 AC_SUBST([sampledir])
diff --git a/src/openvpn/Makefile.am b/src/openvpn/Makefile.am
index 4c18449..188834a 100644
--- a/src/openvpn/Makefile.am
+++ b/src/openvpn/Makefile.am
@@ -27,7 +27,8 @@ AM_CFLAGS = \
 	$(OPTIONAL_CRYPTO_CFLAGS) \
 	$(OPTIONAL_LZO_CFLAGS) \
 	$(OPTIONAL_LZ4_CFLAGS) \
-	$(OPTIONAL_PKCS11_HELPER_CFLAGS)
+	$(OPTIONAL_PKCS11_HELPER_CFLAGS) \
+	-DPLUGIN_LIBDIR=\"${plugindir}\"
 if WIN32
 # we want unicode entry point but not the macro
 AM_CFLAGS += -municode -UUNICODE