the strncasecmp macro defined in rte_os_shim.h is already
defined in MinGW-w64, as a result the compiler prints out
the warning below on function redefinition whenever compiling
a file including the header in debug mode.
Fixed by defining the macro only to the clang compiler.
Fixes: 45d62067c237 ("eal: make OS shims internal") Signed-off-by: Tal Shnaiderman <talshn@nvidia.com> Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>