Adds --enable-doc/--disable-doc, if omitted doc will only be build
if requirements are met. If explicitely enabled, configure script
will fail if requirements are not met.
Issues solved:
* PACKAGE_VERSION was abused for SOVERSION
* unneeded DEP stage
* did not support out-of-tree builds
* no way to turn off silent mode
* overriding CFLAGS at make time was not supported
* no static libs were provided
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Thomas Graf