50. ANSI fake VM

.intro: The ANSI fake VM is an implementation of the MPS VM interface (see design.mps.vm) using only services provided by the ANSI C Library (standard.ansic.7).

.page.size: The VM uses a fake page size, given by the constant VMAN_PAGE_SIZE in config.h.

.align: The VM is aligned to the arena grain size by adding the grain size to the requested size, allocating a block that large using malloc(), then rounding the pointer to the block up to a multiple of the grain size and storing the result in vm->base. The block is stored in vm->block, which is passed to free() in VMFinish().