Fix clean out references to legacy builds in the code.

app/context_switch/main.cpp

@@ -170,7 +170,7 @@ int main() {
 
   for (unsigned int i = 0; i < STACK_SIZE; i++) {
     if (custom_stack_1[i] != MAGIC_NUMBER) {
-      printf("\n\nUsed stack size about %u bytes.\n", (STACK_SIZE - i));
+      printf("\n\nUsed stack size about %lu bytes.\n", (STACK_SIZE - i));
       break;
     }
   }

lib/pls/src/internal/scheduling/scheduler.cpp

 #include "pls/internal/scheduling/scheduler.h"
 
 #include "context_switcher/context_switcher.h"
-
-#include "pls/internal/base/thread.h"
 #include "pls/internal/base/error_handling.h"
 
+#include <thread>
+
 namespace pls::internal::scheduling {
 
 scheduler::scheduler(unsigned int num_threads,
@@ -16,7 +16,6 @@ scheduler::scheduler(unsigned int num_threads,
                                                     reuse_thread,
                                                     base::mmap_stack_allocator{}) {}
 
-
 scheduler::~scheduler() {
   terminate();
 }
@@ -97,7 +96,7 @@ void scheduler::work_thread_work_section() {
     } else {
       failed_steals++;
       if (failed_steals >= num_threads) {
-        base::this_thread::yield();
+        std::this_thread::yield();
       }
     }
   }