On Tue, 2015-03-31 at 09:27 +0200, Klaus Gast wrote: > Hi, > > I am trying to compile openconnect version 7.06 on my Synology NAS DS > 212+ > This works fine up to version 7.04 but if I try to compile 7.06 I always > end up with the following error: > > ============================================================= > ./.libs/libopenconnect.so: undefined reference to `esp_shutdown' > collect2: ld returned 1 exit status > ============================================================= That is defined in esp.c which is compiled unconditionally. Could it be some clash with some system header? Do you see some related warning during compilation?