Fixed thread local trace flags that broke way back in 7.1.10. Took away the --without-thread-trace configure option to make the trace flag always exist in one place. Instead the trace() function is extended to be able to set the trace flag in all threads. Rev: src/acconfig.h:1.111 Rev: src/builtin.cmod:1.104 Rev: src/configure.in:1.673 Rev: src/interpret.h:1.121 Rev: src/main.c:1.161 Rev: src/main.h:1.21 Rev: src/opcodes.c:1.130 Rev: src/pike_threadlib.h:1.26