Summary:
Export __sanitizer_malloc, etc as aliases to malloc, etc.
This way users can wrap sanitizer malloc, even in fully static binaries.
Both jemalloc and tcmalloc provide similar aliases (je_* and tc_*).
Reviewers: vitalybuka, kcc
Subscribers: llvm-commits, kubamracek
Differential Revision: https://reviews.llvm.org/D50570
llvm-svn: 339614