platforms: fix linking issues for NuttX build

boards/px4/fmu-v2/src/init.c

@@ -47,6 +47,7 @@
 
 #include <px4_config.h>
 #include <px4_tasks.h>
+#include <px4_time.h>
 
 #include <stdbool.h>
 #include <stdio.h>

src/include/visibility.h

@@ -101,8 +101,12 @@
 // like uavcan and we don't need to fake time on the real system.
 #include <unistd.h>
 #include <time.h>
+
 #define system_usleep usleep
 #define system_sleep sleep
 
+#define system_clock_gettime clock_gettime
+#define system_clock_settime clock_settime
+
 #pragma GCC poison getenv setenv putenv
 #endif /* __PX4_NUTTX */

src/platforms/px4_time.h

@@ -21,7 +21,7 @@ __EXPORT unsigned int sleep(unsigned int sec);
 
 __END_DECLS
 
-#else
+#elif defined(__PX4_POSIX)
 
 __BEGIN_DECLS
 __EXPORT int px4_clock_gettime(clockid_t clk_id, struct timespec *tp);
@@ -34,4 +34,11 @@ __EXPORT int px4_pthread_cond_timedwait(pthread_cond_t *cond,
 					const struct timespec *abstime);
 __END_DECLS
 
+#elif defined(__PX4_NUTTX)
+
+#define px4_clock_gettime system_clock_gettime
+#define px4_clock_settime system_clock_settime
+#define px4_usleep system_usleep
+#define px4_sleep system_sleep
+
 #endif