Apperently on RHEL / CentOS 5.9 this breaks the compile since these symbols are exported there. Also checked against Ubuntu and the symbols are available there too. Fixes #2217
Problem here was that using assign() also resets the hit counters, leading to wrong heuristics on whether a method is called often or not. In certain cases this could lead to hot methods not being inlined.
We only need to mark this as on stack when internalizing, since only internalize could cause a lock and needs the compiled code object to be updated.
We use the same parsing for 1.8 and 1.9 mode, just the regular expression is different so the new 1.9 style is never matched by the 1.8 regexp. This makes for less duplicate code, while supporting both modes properly. Fixes #1627