Fix VLA and potential stack overflow in GetCallstack on POSIX

The Linux/Mac branch declared a VLA as `void* Frames[FramesToSkip +
FramesToCapture]`, using the caller-supplied frame counts directly as
the stack-allocation size. Two problems: VLAs are a GCC extension, not
standard C++, and any caller that passes (or can be coaxed into
passing) a large or negative value can blow the stack. Even
well-meaning callers can trip this since there is no cap on what
GetCallstack is asked to capture.

Replace the VLA with a fixed-size stack buffer of 256 frames and
clamp the requested count to that bound before calling backtrace(),
which is well above anything useful for practical stack traces.
Include <algorithm> for std::min.

0 files changed, 0 insertions, 0 deletions