This patch fixes huge memory corruption in relibc linux.
The problem is that we have 2 identical copies of relibc ones in ld.so and the other in libc.so
Problem happens when there is transition from on to the other. The issue is that each ofthem has it own rust allocator but both are operating on the same memory space (brk()) but without sharing metadata for who is allocating what. that leaded to huge memory corruption that only appears some of the times. This patchset uses dlmalloc mspaces to do bookkeeping of malloc metadata between 2 copies of libc and rust stdlib instances.