plugins/loader: Clean up global variable shadowing

Fix:

  include/qemu/plugin.h:245:54: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
  static inline void qemu_plugin_opt_parse(const char *optarg,
                                                       ^
  /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/getopt.h:77:14: note: previous declaration is here
  extern char *optarg;                    /* getopt(3) external variables */
               ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231004120019.93101-6-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

include/qemu/plugin.h

@@ -50,7 +50,7 @@ static inline void qemu_plugin_add_opts(void)
     qemu_add_opts(&qemu_plugin_opts);
 }
 
-void qemu_plugin_opt_parse(const char *optarg, QemuPluginList *head);
+void qemu_plugin_opt_parse(const char *optstr, QemuPluginList *head);
 int qemu_plugin_load_list(QemuPluginList *head, Error **errp);
 
 union qemu_plugin_cb_sig {
@@ -242,7 +242,7 @@ void qemu_plugin_user_postfork(bool is_child);
 static inline void qemu_plugin_add_opts(void)
 { }
 
-static inline void qemu_plugin_opt_parse(const char *optarg,
+static inline void qemu_plugin_opt_parse(const char *optstr,
                                          QemuPluginList *head)
 {
     error_report("plugin interface not enabled in this build");

plugins/loader.c

@@ -140,12 +140,12 @@ static int plugin_add(void *opaque, const char *name, const char *value,
     return 0;
 }
 
-void qemu_plugin_opt_parse(const char *optarg, QemuPluginList *head)
+void qemu_plugin_opt_parse(const char *optstr, QemuPluginList *head)
 {
     struct qemu_plugin_parse_arg arg;
     QemuOpts *opts;
 
-    opts = qemu_opts_parse_noisily(qemu_find_opts("plugin"), optarg, true);
+    opts = qemu_opts_parse_noisily(qemu_find_opts("plugin"), optstr, true);
     if (opts == NULL) {
         exit(1);
     }