OOM handling in C

The h3 C library does not handle the case of malloc/calloc/realloc returning NULL in a robust manner. If assertions are enabled, the library crashes, otherwise it will use the NULL pointer leading to undefined behavior. While I understand the convenience of this design in the C library, not propagating OOM errors up the stack means binding code like this is not reliable: https://github.com/uber/h3-java/blob/ed818d3d07c005576c0f96490015f388992b6df8/src/main/c/h3-java/src/jniapi.c#L44 Users are likely to see a sudden fatal crash in the Java process and may not see any hint to the C assertion. Practically, consider using return codes to handle OOM up the stack for your C functions so you can handle them probably here.

Start with the JNI binding entry point mentioned at src/main/c/h3-java/src/jniapi.c#L44, then trace the H3 C functions it calls and their malloc/calloc/realloc handling. Done means out-of-memory failures are propagated through the relevant C and Java binding layers instead of causing assertions or NULL-pointer undefined behavior.