won't compile on raspbian

At least this (in some way) is required:

diff --git a/src/modules/module-rtkit.c b/src/modules/module-rtkit.c
index de30f41..859d5c7 100644
--- a/src/modules/module-rtkit.c
+++ b/src/modules/module-rtkit.c
@@ -183,7 +183,7 @@ void pw_rtkit_bus_free(struct pw_rtkit_bus *system_bus)
 static pid_t _gettid(void)
 {
 #ifndef __FreeBSD__
-       return (pid_t) gettid();
+       return syscall(SYS_gettid);
 #else
        long pid;
        thr_self(&pid);
@@ -518,7 +518,7 @@ static void *custom_start(void *data)
        struct impl *impl = this->impl;
 
        pthread_mutex_lock(&impl->lock);
-       this->pid = gettid();
+       this->pid = _gettid();
        pthread_cond_broadcast(&impl->cond);
        pthread_mutex_unlock(&impl->lock);