support: Add optstring support

This patch adds an option to test to add small command line option
through CMDLINE_OPTSTRING define.  For instance:

  #define CMDLINE_OPTSTRING "vd"

  static void
  cmdline_process_function (int c)
  {
    switch (c):
      'v':
        /* process '-v' option.  */
      break;
      'd':
        /* process '-d' option.  */
      break;
  }
  #define CMDLINE_PROCESS cmdline_process_function

It will add both '-v' and '-d' along with already default long options.

	* support/support_test_main.c (support_test_main):  Use optstring
	member for option string in getopt_long.
	* support/test-driver.c: Add comment about CMDLINE_OPTSTRING.
	(CMDLINE_OPTSTRING): New define.
	* support/test-driver.h (test_config): Add optstring member.

ChangeLog

@@ -1,3 +1,11 @@
+2017-06-15  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+	 * support/support_test_main.c (support_test_main):  Use optstring
+	 member for option string in getopt_long.
+	 * support/test-driver.c: Add comment about CMDLINE_OPTSTRING.
+	 (CMDLINE_OPTSTRING): New define.
+	 * support/test-driver.h (test_config): Add optstring member.
+
 2017-06-15  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add

support/support_test_main.c

@@ -211,7 +211,8 @@ support_test_main (int argc, char **argv, const struct test_config *config)
         mallopt (M_PERTURB, 42);
     }
 
-  while ((opt = getopt_long (argc, argv, "+", options, NULL)) != -1)
+  while ((opt = getopt_long (argc, argv, config->optstring, options, NULL))
+	 != -1)
     switch (opt)
       {
       case '?':

support/test-driver.c

@@ -93,6 +93,10 @@
    has this type:
 
      void CMDLINE_PROCESS (int);
+
+   If the program also to process custom default short command line
+   argument (similar to getopt) it must define CMDLINE_OPTSTRING
+   with the expected options (for instance "vb").
 */
 
 #include <support/test-driver.h>
@@ -151,6 +155,11 @@ main (int argc, char **argv)
 #ifdef CMDLINE_PROCESS
   test_config.cmdline_function = CMDLINE_PROCESS;
 #endif
+#ifdef CMDLINE_OPTSTRING
+  test_config.optstring = "+" CMDLINE_OPTSTRING;
+#else
+  test_config.optstring = "+";
+#endif
 
   return support_test_main (argc, argv, &test_config);
 }

support/test-driver.h

@@ -35,6 +35,7 @@ struct test_config
   int expected_status;   /* Expected exit status.  */
   int expected_signal;   /* If non-zero, expect termination by signal.  */
   char no_mallopt;       /* Boolean flag to disable mallopt.  */
+  const char *optstring; /* Short command line options.  */
 };
 
 enum