Unfortunately, we can't just add the generated C file to the sources in
Makefile.am as the linker would remove that object file when it notices
that no symbol in it is ever referenced. So we include it in the file
that contains the library initialization, which will definitely be
referenced by the executable.
This allows building an almost stand-alone static version of e.g. charon
when building with `--enable-monolithic --enable-static --disable-shared`
(without `--disable-shared` libtool will only build a version that links
the libraries dynamically). External libraries (e.g. gmp or openssl) are
not linked statically this way, though.
The flag is required to convince libtool on Cygwin to build DLLs. But on
Windows these shared libraries can not have undefined symbols, so we have to
link them explicitly to the libraries they reference.
For plugins this is currently not done, so only the monolithic build is
supported. The plugin loader wouldn't be able to load DLLs anyway, as
it tries to load files that don't exist on Cygwin.
INCLUDES are now deprecated and throw warnings when using automake 1.13.
We now also differentiate AM_CPPFLAGS and AM_CFLAGS, where includes and
defines are passed to AM_CPPFLAGS only.