Support valgrind for ST

[winlinvip]

Valgrind is very useful toolkit for memory leak detect and memory corrupt check, but not support ST for the setjmp/longjmp. Maybe we can patch ST to support valgrind.

[winlinvip]

toffaletti already support this feature, we can merge this fork.

[winlinvip]

We just need to tell valgrind the stack we allocate, by macro VALGRIND_STACK_REGISTER and VALGRIND_STACK_DEREGISTER

The usage: https://github.com/ossrs/state-threads/tree/srs#usage

[winlinvip]

For valgrind usage: https://github.com/ossrs/state-threads/tree/srs#valgrind

[winlinvip]

SRS3 already use state-threads-1.9.1.tar.gz, which is the latest ST, patched to support Valgrind.