Compiler warnings are now accumulated in a vector of strings within the mjSpec object. New API functions `mjs_numWarnings` and `mjs_getWarning` are added to access these warnings. The compiler's log handler now chains warnings to the global log handler, ensuring they are still displayed immediately. Call sites in `mj_loadXML`, `mj_compile`, and the Python and WASM bindings have been updated to use the new warning API.
PiperOrigin-RevId: 933361650
Change-Id: I47cab98a460c57b0898c0a1a43fce2a5b9648eb1
Also add asan instrumentation to detect stack frame leakages (i.e. `mj_markStack` without a corresponding `mj_freeStack` in the same caller function).
PiperOrigin-RevId: 562625645
Change-Id: I4e3ff66ca0b9d08ed0a95cef45393db8e3053e22
Kyle Bayes