Get Odin compiling and produced exe's running on FreeBSD

core/sync/channel_unix.odin

@@ -1,4 +1,4 @@
-// +build linux, darwin
+// +build linux, darwin, freebsd
 package sync
 
 import "core:time"

core/sync/sync_freebsd.odin

@@ -0,0 +1,32 @@
+package sync
+
+import "core:sys/unix"
+
+// The Darwin docs say it best:
+// A semaphore is much like a lock, except that a finite number of threads can hold it simultaneously.
+// Semaphores can be thought of as being much like piles of tokens; multiple threads can take these tokens, 
+// but when there are none left, a thread must wait until another thread returns one.
+Semaphore :: struct #align 16 {
+	handle: unix.sem_t,
+}
+
+semaphore_init :: proc(s: ^Semaphore, initial_count := 0) {
+	assert(unix.sem_init(&s.handle, 0, u32(initial_count)) == 0);
+}
+
+semaphore_destroy :: proc(s: ^Semaphore) {
+	assert(unix.sem_destroy(&s.handle) == 0);
+	s.handle = {};
+}
+
+semaphore_post :: proc(s: ^Semaphore, count := 1) {
+    // NOTE: SPEED: If there's one syscall to do this, we should use it instead of the loop.
+    for in 0..count-1 {
+	    assert(unix.sem_post(&s.handle) == 0);
+    }
+}
+
+semaphore_wait_for :: proc(s: ^Semaphore) {
+	assert(unix.sem_wait(&s.handle) == 0);
+}
+

core/sync/sync_unix.odin

@@ -1,4 +1,4 @@
-// +build linux, darwin
+// +build linux, darwin, freebsd
 package sync
 
 import "core:sys/unix"