Use `make STATIC=1` to build a static library.
Some language ecosystems, like those of Rust, have a convention of
static linking in order to make binaries easier to distribute. In those
environments, this feature helps libui fit in more easily.
In order to prevent internal symbols from linking, we first create an
intermediate object file with `ld -r` and strip private symbols from it
before using `ar` to create the library.
* $PREFIX is uppercase (I have no idea why I put it lowercase before).
* "install" rules is OS specific and moved to new OS specific files. So that they can be included last.
* "examples" rule defines the list of examples to execute.
* Travis launches the "test" rule.
Patrick Walton
Pietro Gagliardi
Florent Clairambault