ci: stop using pull_request event, use push

We can't access github's secrets from a pull_request event (for security
reasons).

Use the push event, and try not to send emails when we should not.

Signed-off-by: Marc Poulhiès <dkm@kataplop.net>

Author: dkm

gcc/rust/rust-lang.cc

@@ -285,7 +285,7 @@ grs_langhook_handle_option (
 
 /* Run after parsing options.  */
 static bool
-grs_langhook_post_options (const char **pfilename ATTRIBUTE_UNUSED)
+grs_langhook_post_options (const char **pfilename)
 {
   // can be used to override other options if required
 

gcc/rust/rust-session-manager.cc

@@ -399,9 +399,9 @@ Session::enable_dump (std::string arg)
 void
 Session::handle_input_files (int num_files, const char **files)
 {
+  static const char *stdin_file[] = {"-"};
   if (num_files == 0)
     {
-      static const char *stdin_file[] = {"-"};
       files = stdin_file;
       num_files = 1;
     }