Do not handle SIGURG on Linux, as in go1.14+, the go runtime issues
SIGURG as an interrupt to support preemptable system calls on Linux.
This issue was caught in TestCatchAll, which could fail when updating to Go 1.14 or above;
=== Failed
=== FAIL: pkg/signal TestCatchAll (0.01s)
signal_linux_test.go:32: assertion failed: urgent I/O condition (string) != continued (string)
signal_linux_test.go:32: assertion failed: continued (string) != hangup (string)
signal_linux_test.go:32: assertion failed: hangup (string) != child exited (string)
signal_linux_test.go:32: assertion failed: child exited (string) != illegal instruction (string)
signal_linux_test.go:32: assertion failed: illegal instruction (string) != floating point exception (string)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Sebastiaan van Stijn