[ruby-cvs:71120] kazu:r64029 (trunk): Try to suppress warning on some CI

[kazu at ruby-lang.org]

kazu	2018-07-24 18:15:58 +0900 (Tue, 24 Jul 2018)

  New Revision: 64029

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=64029

  Log:
    Try to suppress warning on some CI
    
    http://ci.rvm.jp/results/trunk-asserts-nopara@silicon-docker/1149270
    ```
    /home/ko1/ruby/src/trunk-asserts-nopara/process.c: In function 'assert_close_on_exec':
    /home/ko1/ruby/src/trunk-asserts-nopara/process.c:298:9: warning: ignoring return value of 'write', declared with attribute warn_unused_result [-Wunused-result]
             (void)write(2, m, sizeof(m) - 1);
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ```
    
    workaround from https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34

  Modified files:
    trunk/process.c