Now that PASS_INFO() exists, use it in the other existing gcc plugins,
instead of always open coding the same thing.

Based on updates to the grsecurity/PaX gcc plugins.

Signed-off-by: Kees Cook <keescook@chromium.org>

This explicitly exports symbols that gcc expects from plugins.

Based on code from Emese Revfy.

Signed-off-by: Kees Cook <keescook@chromium.org>

Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC
plugin computes the cyclomatic complexity of each function.

The complexity M of a function's control flow graph is defined as:
M = E - N + 2P
where
E = the number of edges
N = the number of nodes
P = the number of connected components (exit nodes).

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>