This patch make the ABI mechanism available to shared libraries other
than Genode's dynamic linker. It thereby allows us to introduce
intermediate ABIs at the granularity of shared libraries. This is useful
for slow-moving ABIs such as the libc's interface but it will also
become handy for the package management.
To implement the feature, the build system had to be streamlined a bit.
In particular, archive dependencies and shared-lib dependencies are now
handled separately, and the global list of 'SHARED_LIBS' is no more.
Now, the variable with the same name holds the per-target list of shared
libraries used by the target.
This patch removes the component_entry_point library, which used to
proved a hook for the libc to intercept the call of the
'Component::construct' function. The mechansim has several shortcomings
(see the discussion in the associated issue) and was complex. So we
eventually discarded the approach in favor of the explicit handling of
the startup.
A regular Genode component provides a 'Component::construct' function,
which is determined by the dynamic linker via a symbol lookup.
For the time being, the dynamic linker falls back to looking up a 'main'
function if no 'Component::construct' function could be found.
The libc provides an implementation of 'Component::construct', which
sets up the libc's task handling and finally call the function
'Libc::Component::construct' from the context of the appllication task.
This function is expected to be provided by the libc-using application.
Consequently, Genode components that use the libc have to implement the
'Libc::Component::construct' function.
The new 'posix' library provides an implementation of
'Libc::Component::construct' that calls a main function. Hence, POSIX
programs that merely use the POSIX API merely have to add 'posix' to the
'LIBS' declaration in their 'target.mk' file. Their execution starts at
'main'.
Issue #2199
This patch makes the build-system integration of noux packages usable
for non-Noux targets. It moves the GNU build system wrapper to
ports/mk/gnu_build.mk, which is now included by noux.mk. This way,
non-noux applications can use the same build-system wrapper. So the
porting of individual applications becomes easier.
This change removes the 'NOUX_' prefix use the various build variables
used by the noux-pkg's target.mk files to steer the behaviour of the GNU
build system. E.g., NOUX_CONFIGURE_ARGS is now called CONFIGURE_ARGS.
Note that there is a single exception to this pattern: The formerly
named NOUX_LIBS is now called LDLIBS because the plain LIBS variable is
used by the Genode build system.
Fixes#2094
