move rc_svcdir to /run/openrc on Linux systems

If you are not using linux, this should not affect you.

If you are using linux, from this point forward, openrc requires the
/run directory to be a mounted tmpfs. If it is, you can run
@LIBEXECDIR@/sh/migrate-to-run.sh as root to migrate your dependency
tree and state information to the new location. If it is not, you must
create the /run directory as root with permissions 755 then reboot your
system.

reported-by: Maxim Kammerer <mk@dee.su>
X-Gentoo-Bug: 401059
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=401059

src/librc/rc.h.in

@@ -36,7 +36,11 @@ __BEGIN_DECLS
 #define RC_SYSCONFDIR		"@SYSCONFDIR@"
 #define RC_LIBDIR               "@PREFIX@/@LIB@/rc"
 #define RC_LIBEXECDIR           "@LIBEXECDIR@"
+#ifdef __linux__
+#define RC_SVCDIR               "@PREFIX@/run/openrc"
+#else
 #define RC_SVCDIR               RC_LIBEXECDIR "/init.d"
+#endif
 #define RC_RUNLEVELDIR          RC_SYSCONFDIR "/runlevels"
 #define RC_INITDIR              RC_SYSCONFDIR "/init.d"
 #define RC_CONFDIR              RC_SYSCONFDIR "/conf.d"