In ecl/config.h line 220 there is a block labelled /* Missing integer types */
The int8_t has a typedef of char which is incompatible with Windows standard types.
changing line 221 from:
typedef char int8_t;
to
typedef signed char int8_t;
Fixes the issue for me and allows me to compile both lisp code and C++ projects using ecl.lib
I know that char and signed char should be the same but the MS VS compile disagrees.