CI: github actions: add the output of $CC -dM -E-

Sometimes figuring what differs between platforms is useful to fix
build issues, to decide what ifdef to add for example. Let's always
call $CC -dM -E- before starting make.

(cherry picked from commit 4673c5e2c81e8e2b04018f3ba0b80d41d85f2220)
Signed-off-by: William Lallemand <wlallemand@haproxy.org>
(cherry picked from commit c9495592634ec4c4e85dd47715437d8cb6b2286a)
Signed-off-by: William Lallemand <wlallemand@haproxy.org>
2 files changed