[bug-mes] MesCC neglects alignment requirements of the System V ABI

[Mark H Weaver]

The System V ABI specifies alignment requirements for each C type.
Padding must be implicitly inserted in structures to ensure that each
field is properly aligned.  MesCC does not do this, and therefore it
violates the ABI.

For example, see section 3.1.2 (Data Representation) here:

  
https://software.intel.com/sites/default/files/article/402129/mpx-linux64-abi.pdf

One consequence of this is that MesCC-compiled code cannot reliably be
linked with code compiled by other compilers, because there may be
disagreements over structure layout.

       Mark