rpmlib-sys: rpmts.h and rpmfi.h cause `bindgen_test_layout_max_align_t` failures

[tony-iqlusion]

These headers are:

• rpmts.h: Transaction sets
• rpmfi.h: File information

When either of these headers are enabled (in src/rpmlib-sys.h), they cause the automatically generated bindgen_test_layout_max_align_t test to fail. In either case, we get the following failure:

---- bindgen_test_layout_max_align_t stdout ----
	thread 'bindgen_test_layout_max_align_t' panicked at 'assertion failed: `(left == right)`
  left: `24`,
 right: `32`: Size of: max_align_t', target/debug/build/rpmlib-sys-25076a13bc63918f/out/bindings.rs:6564:5

Both of these headers are presently commented out in the binding generator due to these errors.

[tony-iqlusion]

Transaction sets are an integral part of rpmlib's API, and without them we're blocked on doing pretty much anything (#13, #14, #15, #16).

[tony-iqlusion]

These were both fixed in #17 by having bindgen build a C++ binding instead of a C one

[tony-iqlusion]

Per rust-lang/rust-bindgen#363 it sounds like this issue would've also been addressed by using rust_target(1.25) now that repr(align(N)) is stable.