Add multithread quit function

Author: Critsium-xy

source/module_base/tool_quit.cpp

@@ -1,6 +1,8 @@
 #include "tool_quit.h"
 #ifdef __MPI
 #include "mpi.h"
+#include "module_base/parallel_global.h"
+#include "module_base/parallel_comm.h"
 #endif
 
 #ifdef __NORMAL
@@ -55,6 +57,20 @@ void QUIT(int ret)
     std::cout<<" See output information in : "<<PARAM.globalv.global_out_dir<<std::endl;
 #endif
 
+#ifdef _OPENMP // merge all threads of one process into one thread
+	if (omp_in_parallel())
+	{
+		omp_set_num_threads(1);
+		std::cout << "Terminating ABACUS with multithreading environment." << std::endl;
+	}
+	assert(!omp_in_parallel()); /* avoid the case that death thread calls fork() */
+#endif
+
+#ifdef __MPI /* if it is MPI run, finalize first, then exit */
+	std::cout << "Terminating ABACUS with multiprocessing environment." << std::endl;
+	Parallel_Global::finalize_mpi();
+	/* but seems this is the only correct way to terminate the MPI */
+#endif
     exit(ret);
 }