build: Provide modules-load.d for loading pkcs8_key_parser module

Makefile.am

@@ -142,6 +142,9 @@ systemd_unit_DATA =
 
 dbus_busdir = @DBUS_BUSDIR@
 dbus_bus_DATA =
+
+systemd_modloaddir = @SYSTEMD_MODLOADDIR@
+systemd_modload_DATA = src/pkcs8.conf
 endif
 
 eap_sources = src/eap.c src/eap.h src/eap-private.h \

configure.ac

@@ -209,6 +209,19 @@ if (test "${enable_systemd_service}" != "no" && test -z "${path_systemd_unitdir}
 fi
 AC_SUBST(SYSTEMD_UNITDIR, [${path_systemd_unitdir}])
 
+AC_ARG_WITH([systemd-modloaddir], AC_HELP_STRING([--with-systemd-modloaddir=DIR],
+				[path to systemd modules load directory]),
+					[path_systemd_modloaddir=${withval}])
+if (test "${enable_systemd_service}" != "no" && test -z "${path_systemd_modloaddir}"); then
+	AC_MSG_CHECKING([systemd modules load directory])
+	path_systemd_modloaddir="`$PKG_CONFIG --variable=modulesloaddir systemd`"
+	if (test -z "${path_systemd_modloaddir}"); then
+		AC_MSG_ERROR([systemd modules load directory is required])
+	fi
+	AC_MSG_RESULT([${path_systemd_modloaddir}])
+fi
+AC_SUBST(SYSTEMD_MODLOADDIR, [${path_systemd_modloaddir}])
+
 AC_ARG_ENABLE([external_ell], AC_HELP_STRING([--enable-external-ell],
 				[enable external Embedded Linux library]),
 					[enable_external_ell=${enableval}])

src/pkcs8.conf

@@ -0,0 +1,5 @@
+# When distributions use CONFIG_PKCS8_PRIVATE_KEY_PARSER=m kernel option,
+# using keyctl(2) will fail for loading PKCS#8 private keys since there is
+# no automatic module loading for key type parsers.  This entry ensures
+# that the kernel module pkcs8_key_parser.ko is loaded at boot time.
+pkcs8_key_parser