Avoid C++-style comments.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

tests/lib/mcconfig/config_string.c

@@ -188,7 +188,7 @@ main (void)
 
     suite_add_tcase (s, tc_core);
     sr = srunner_create (s);
-//    srunner_set_fork_status (sr, CK_NOFORK);
+    /* srunner_set_fork_status (sr, CK_NOFORK); */
     srunner_run_all (sr, CK_NORMAL);
     number_failed = srunner_ntests_failed (sr);
     srunner_free (sr);

tests/lib/mcconfig/user_configs_path.c

@@ -132,7 +132,7 @@ main (void)
     suite_add_tcase (s, tc_core);
     sr = srunner_create (s);
     srunner_set_log (sr, "user_configs_path.log");
-//    srunner_set_fork_status (sr, CK_NOFORK);
+    /* srunner_set_fork_status (sr, CK_NOFORK); */
     srunner_run_all (sr, CK_NORMAL);
     number_failed = srunner_ntests_failed (sr);
     srunner_free (sr);

tests/lib/name_quote.c

@@ -59,14 +59,14 @@ static const struct data_source1_struct
 
 START_TEST (quote_percent_test)
 {
-    // given
+    /* given */
     char *actual_string;
     const struct data_source1_struct test_data = data_source1[_i];
 
-    // when
+    /* when */
     actual_string = name_quote (test_data.input_string, test_data.input_quote_percent);
 
-    // then
+    /* then */
     g_assert_cmpstr (actual_string, ==, test_data.expected_string);
 
     g_free (actual_string);
@@ -95,14 +95,14 @@ static const struct data_source2_struct
 
 START_TEST (name_quote_test)
 {
-    // given
+    /* given */
     char *actual_string;
     const struct data_source2_struct test_data = data_source2[_i];
 
-    // when
+    /* when */
     actual_string = name_quote (test_data.input_string, FALSE);
 
-    // then
+    /* then */
     g_assert_cmpstr (actual_string, ==, test_data.expected_string);
 
     g_free (actual_string);

tests/src/filemanager/exec_get_export_variables_ext.c

@@ -69,7 +69,7 @@ teardown (void)
 
 START_TEST (sanitize_variables)
 {
-    // given
+    /* given */
     vfs_path_t * filename_vpath;
     char *actual_string;
     const char *expected_string;
@@ -82,12 +82,12 @@ START_TEST (sanitize_variables)
     current_panel->dir.list[2].f.marked = TRUE;
     current_panel->count = 3;
 
-    // when
+    /* when */
     filename_vpath = vfs_path_from_str("/tmp/blabla.txt");
     actual_string = exec_get_export_variables (filename_vpath);
     vfs_path_free (filename_vpath);
 
-    // then
+    /* then */
     expected_string = "\
 MC_EXT_FILENAME=/tmp/blabla.txt\n\
 export MC_EXT_FILENAME\n\