In case of optimized compilation, RTE_BUILD_BUG_ON use an external
variable which is neither defined, nor used.
It seems not optimized out in case of OPDL compiled with clang -O1:
opdl_ring.c: undefined reference to `RTE_BUILD_BUG_ON_detected_error'
clang-6.0: fatal error: linker command failed with exit code 1
Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
e357e8ebd9