[PATCH 0/4] malloc_info: minor fixes and improvements [BZ #17039]

[Ken Milmore]

PING.

These patches are intended is to rectify a couple of problems with the
output of malloc_info(), to make it useful as a more detailed
alternative to mallinfo() and malloc_stats(). Namely:

1. The reported chunk sizes are typically off by a few bytes (BZ#17039)
2. The size(s) of the "top" heap chunk(s) are not accounted for.

There is also a new unit test to check that the respective outputs of
malloc_info and mallinfo agree exactly.

https://sourceware.org/ml/libc-alpha/2018-05/msg00783.html
https://sourceware.org/ml/libc-alpha/2018-05/msg00785.html
https://sourceware.org/ml/libc-alpha/2018-05/msg00784.html
https://sourceware.org/ml/libc-alpha/2018-05/msg00786.html