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 tpm plugin can be used to derive true random numbers from a
TPM 2.0 device. The get_random method must be explicitly enabled
in strongswan.conf with the plugin.tpm.use_rng = yes option.