- Align DLLEXPORT in definitions and declations. There is still a few
cases left, where the declation in the compiler's complex.h disagrees
with the implementation here. For now we can't do anything about that,
but maybe should be revisited in the future.
- Fix the syntax on an .ascii directive that gcc accepted mistakingly, but
clang does not.
This is a bit more consistent with the naming of the other header files
(openlibm_complex.h and openlibm_fenv.h). Re-add an openlibm.h header
that includes all of the public headers as a shorthand.
Fix up all of the source files to include <openlibm_math.h> instead of
<openlibm.h>. While there, fix ordering of the includes.
Put external headers before internal ones. While there, replace a lot of
occurences of "openlibm.h" with <openlibm.h>. It should be thought of as
an external header, as it is installed along with the library.