Clang fixes

-Wundef fix in TuxDef.h
-Wshadow in MR.c, size was already used
-Wdocumentation in ErrCodes.c
CM.c: pointer arithmetic on void* is a GNU extension
SendData.h: add extern for -Wmissing-variable-declarations
ErrCodes.c/h: format string for LogCip() should be const
AB.h: add missing enumerations