Thread-safe runtime system

[Martin Sjölund]

This is a collection of non-threadsafe parts that we probably should resolve for bootstrapping if we want to run parallel omc:

• Message system (buffers)
• Jump buffers (setjmp; global, stack overflow, simulation stuff (less important))
• Java runtime (does anyone care?)
• Compiler/runtime: Need to consider error-buffers in parallel. Probably each thread wants its own error-stack to manipulate
• More?

[Martin Sjölund]

Thread-local storage possible to mimic globals

[Martin Sjölund]

pthread_rwlock_t to lock most global variables (we write to them very rarely, but we should lock them anyway).