We might want a secondary instrument for this eventually, but for now we'll
just attach it in the Linux instrument.
This takes the output of eglinfo and glxinfo and adds it as a file in the
capture syscap. Compressed of course to keep the size smaller.
This brings together the two libraries back into one now that the whole
design is pretty well sorted out. They depend on roughly the same libraries
anyway and it's way easier of the single library can both read and write
the capture files (along with bringing in libsysprof-capture symbols in
a single place).
