BUILD/MEDIUM: deviceatlas: fix when installed in custom locations.

BUILD/MEDIUM: deviceatlas: fix when installed in custom locations.

We are reusing DEVICEATLAS_INC/DEVICEATLAS_LIB when the DeviceAtlas
library had been compiled and installed with cmake and make install targets.
Works fine except when ldconfig is unaware of the path, thus adding
cflags/ldflags into the mix.

Ideally, to be backported down to the lowest stable branch.

(cherry picked from commit 0e8e20a83f4dd789443b9176cd93573bcfa75c20)
Signed-off-by: William Lallemand <wlallemand@haproxy.com>
(cherry picked from commit 770ad55db942bc69d436939bfdf1a7072d5572f9)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit f1dcfdd56cb24260b5c1884941f037a29edc83cb)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>