Build nucleo-144/f767-netnsh fail with below error:
In file included from igmp/igmp_initialize.c:54:
./igmp/igmp.h:130:3: error: unknown type name 'sem_t'
130 | sem_t sem; /* Used to wait for message transmission */
| ^~~~~
make[1]: *** [igmp_initialize.o] Error 1
Signed-off-by: liuhaitao <liuhaitao@xiaomi.com>