Process polling api

src/basic/filesystem.h

@@ -34,11 +34,20 @@ bool   IsFile(String path);
 String GetWorkingDir(Allocator arena);
 bool   IsAbsolute(String path);
 
+struct StdoutPollInfo {
+    int64_t size_read;
+    int64_t size_available;
+};
+
 struct Process {
     bool   is_valid;
     String error_message;
-    char   platform[32];
+    int    exit_code;
+    char   platform[6 * 8];
 };
 
-Process RunEx(String cmd);
-int     Wait(Process *process);
+Process        RunCmd(String command_line, String working_dir);
+bool           WaitForExit(Process *process);
+bool           PollExitCode(Process *process);
+void           KillProcess(Process *process);
+StdoutPollInfo PollStdout(Process *process, char *buffer, int64_t buffer_size);