Alexandre Rostovtsev authored Sep 30, 2011 and David King committed Dec 17, 2011

Fix numerous vinagre_utils_* and vinagre_dirs_* implicit function
declarations by generating a header (vinagre/vinagre-vala.h) from the
vala source and including it in half the .c files in the source tree.

Add the vinagre-vala.h to dist_noinst_DATA to make sure it goes in the
release tarballs, and to BUILT_SOURCES to ensure that it is generated
before the C sources that #include it are compiled. Add
-I$(top_srcdir)/vinagre to CPPFLAGS so that vinagre-vala.h is picked up
in out-of-tree builds.

Unfortunately, automake does not support per-target VALAFLAGS. We cannot
simply add a "--header vinagre/vinagre-vala.h" option to AM_VALAFLAGS
or VALAFLAGS because if we ever use a .vala file in another target (such
as one of the vinagre plugins), vinagre-vala.h will get clobbered.

The only way to prevent valac from running multiple times and safely
support parallel make without adding a ticking time bomb that could
clobber vinagre-vala.h is to manually write a stamp target for the vala
sources used in libvinagre, and manually pass a --header argument to
valac in the rule for the stamp.

Pick "vinagre_vala.stamp" as the name for it to avoid potential
collisions with automake's vala stamp naming conventions, and make sure
to add the stamp to dist_noinst_DATA so that people who download the
source tarball are not forced to use vala to build vinagre.

Also, add an explicit rule for generating vinagre-vala.h for those who
do not have it and are building from git (otherwise, make will fail due
to the presense of vinagre-vala.h in dist_noinst_DATA).

Since vala sources are not in vinagre_vinagre_SOURCES any more, we have
to add them to dist_noinst_DATA so that they are added to release
tarballs.