Implement userspace TLS, remove RW Locks

kernel/proc/procgroup.h

@@ -7,6 +7,7 @@
 #include <proc/resource.h>
 #include <sync/spin_lock.h>
 #include <sys/mm.h>
+#include <sys/procgroup.h>
 
 struct proc;
 
@@ -29,6 +30,7 @@ struct procgroup {
   struct pd pd;
   struct list_node_link* mappings;
   uintptr_t map_base;
+  struct procgroup_tls tls;
 };
 
 struct procgroup* procgroup_create (void);