Beautify tests.

config/checksrc/test_mpi_pack_external_1.c

-#include <mpi.h>
 #include <stdlib.h>
 #include <stdio.h>
 
+#include <mpi.h>
+
 static void mpi_err_handler(int error_code, MPI_Comm comm);
 
-char const * datarep = "external32";
+static const char datarep[] = "external32";
 
-#define UINT_COUNT (2)
-#define DBLE_COUNT (24)
+enum {
+  UINT_COUNT = 2,
+  DBLE_COUNT = 27,
+};
 
-int main(void) {
+int main(int argc, char **argv) {
 
-  MPI_Init(NULL, NULL);
+  MPI_Init(&argc, &argv);
 
   unsigned * uint_data = calloc(UINT_COUNT, sizeof(*uint_data));
   double * dble_data = calloc(DBLE_COUNT, sizeof(*dble_data));

config/checksrc/test_mpi_pack_external_2.c

@@ -4,7 +4,7 @@
 
 static void mpi_err_handler(int error_code, MPI_Comm comm);
 
-char const * datarep = "external32";
+static const char datarep[] = "external32";
 
 int main(void) {