proc/gdbserial: add syscall.Syscall* to list of blocking functions
proc/gdbserial: add syscall.Syscall* to list of blocking functions

Fixes #1227

go-delve/delve,alexbrainman/delve,dr2chase/delve,aarzilli/delve,dr2chase/delve,alexbrainman/delve,go-delve/delve,alexbrainman/delve,dr2chase/delve,go-delve/delve,go-delve/delve,aarzilli/delve,derekparker/delve,go-delve/delve,derekparker/delve,aarzilli/delve,derekparker/delve,aarzilli/delve