* better support of C89 standart
* VC6 fixes
* __pragma attribute works for _MSC_VER > 1400
* use intptr_t for char*
* C89 has no designated initializers
* correct _MSC_VER versions
* fix check
* add stdint.h for old MSVC versions
Taken from https://github.com/mattn/gntp-send/blob/master/include/msinttypes/stdint.h
* add stdint.h to miniz.h
* make packaging work without Python
* fix window_position initialization
* replace PACKED_STRUCT with i_packed_start.h i_packed_end.h
Thus, we do not use variadic macros from C99.
* undo cmake install changes
* fix icon for VC6
* remove DESCRIPTION and HOMEPAGE_URL from project()
* remove i_packed_start.h and i_packed_end.h
* whitespace fixes
* rename PACKEDPREFIX->PACKED_PREFIX and PACKEDATTR->PACKED_SUFFIX
* MINGW check doesn't work this early
* add check for minimum cmake version for MINGW targets
