Restructure the Makefiles in .sources, .am and .win32 to enable
building cairo-script-interpreter on Win32.
Some minor changes are needed to compile on MSVC:
- include stdint.h to define INT_MAX-like macros
- redefine "inline"
- avoid deprecated functions (snprintf, replaced by _snprintf)
- define _USE_MATH_DEFINES so that math.h defines M_PI, M_SQRT2 and
M_LN2
