eliminate mach_task_self from linux_stubs

guard stray usage of mach_task_self with #if HAVE_MACH
and remove mach_test_self() from linux_stubs.

Author: dgrove-oss

src/data.c

@@ -155,10 +155,12 @@ _dispatch_data_destroy_buffer(const void* buffer, size_t size,
 		free((void*)buffer);
 	} else if (destructor == DISPATCH_DATA_DESTRUCTOR_NONE) {
 		// do nothing
+#if HAVE_MACH
 	} else if (destructor == DISPATCH_DATA_DESTRUCTOR_VM_DEALLOCATE) {
 		mach_vm_size_t vm_size = size;
 		mach_vm_address_t vm_addr = (uintptr_t)buffer;
 		mach_vm_deallocate(mach_task_self(), vm_addr, vm_size);
+#endif
 	} else {
 		if (!queue) {
 			queue = dispatch_get_global_queue(

src/shims/linux_stubs.c

@@ -42,9 +42,6 @@ void mach_vm_deallocate() { LINUX_PORT_ERROR();  }
 mach_port_t pthread_mach_thread_np(void) {
   return (pid_t)syscall(SYS_gettid);
 }
-mach_port_t mach_task_self(void) {
-  return (mach_port_t)pthread_self();
-}
 
 /*
  * Stubbed out static data

src/shims/linux_stubs.h

@@ -62,8 +62,6 @@ typedef void (*dispatch_mach_handler_function_t)(void*, dispatch_mach_reason_t,
 
 typedef void (*dispatch_mach_msg_destructor_t)(void*);
 
-mach_port_t mach_task_self();
-
 // Print a warning when an unported code path executes.
 #define LINUX_PORT_ERROR()  do { printf("LINUX_PORT_ERROR_CALLED %s:%d: %s\n",__FILE__,__LINE__,__FUNCTION__); } while (0)