ref: ccd1b1585da94843f04bbc7b8bf27ebace5cee3c
dir: /src/libc/arch/amd64/darwin/_getheap.c/
static char heap[16384]; void * _getheap(void) { return heap; } void * _brk(void *addr) { static char *cur = heap; char *p = addr; if (p < heap || p > &heap[sizeof(heap) - 1]) return (void *)-1; return cur = p; }