BlockArena, a bit of allocator rework

src/basic/basic_os.cpp

@@ -442,7 +442,7 @@ API String ReadFile(Allocator arena, String path) {
     }
 
     if (!success) {
-        Dealloc(arena, &result.data);
+        Dealloc(arena, result.data);
         result = {};
     }
 
@@ -566,7 +566,7 @@ API String GetExePath(Allocator allocator) {
 }
 
 API String GetExeDir(Allocator allocator) {
-    Scratch scratch((Arena *)allocator.object);
+    Scratch scratch(allocator);
     String  path = GetExePath(scratch);
     path         = ChopLastSlash(path);
     path         = Copy(allocator, path);
@@ -852,7 +852,7 @@ API String PollStdout(Allocator allocator, Process *process, bool force_read) {
     bool  read_error = ReadFile(p->child_stdout_read, buffer, (DWORD)buffer_size, &bytes_read, 0) == 0;
     if (read_error) {
         Win32ReportError("Failed to read the stdout of child process", "ReadFile");
-        Dealloc(allocator, &buffer);
+        Dealloc(allocator, buffer);
         Win32CloseProcess(process);
         return {};
     }