config-parser: export functions to open a config file

The in-tree clients can access the functions via libshared, but they are
currently not available for external clients, such as custom shell helper
applications similar to weston-desktop-shell or
weston-ivi-shell-user-interface.
The functions to read the content of the config are already exported.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
2 jobs for config-parser-export in 4 minutes and 11 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #101783
build-native-autotools

00:04:11

passed #101784
build-native-meson

00:02:50