use only standard c for portability

- builds in gcc with -std=c99 -pedantic
- modrepo.c depends on platform-specific stuff, use some tricks here
use "unsigned int" for uintptr_t typedef

- makes it work with MSVC, which provides its own version of uintptr_t without
  stdint.h
automatic dependencies for core mkd64 files
automatic dependencies for everything
fix clean targets for windows
bugfix: make automatic deps work on windows
changes in Makefile should cause rebuild
consistent formatting and rules order in Makefile
silence dh_shlibdeps by using -static-libgcc
make multi-pass work again

recent mkd64_run() refactoring broke multi-pass disk image generation.
fixed and commented the code, so errors here will be easier to avoid.
automatic remake when given different config

- changing DEBUG, GCC32 or anything resulting in a different libdir causes
  make to remake all
- makefile now uses non-deferred variable assignment where possible
simpler makefile, checkconf is not needed!
force buildid update when new binaries are created
simplified dependency generation

- use "advanced" GCC options
API change: name IModule destructor "free"

- to make it usable from C++
bugfix: fix calculation of version info length
test new object design in cmdline

- let the caller do the allocation (needed for inheritance)
- hide this in macros OBJNEW() and OBJDEL()
new object design globally applied
compatibility for C++ modules
fix gcc warnings on win32

- some leftover return-values in modrepo.c removed