make monitor.so for performance. (#2576)

Recent monitor.rb has performance problem because of interrupt
handlers. 'Monitor#synchronize' is frequently used primitive
so the performance of this method is important.

This patch rewrite 'monitor.rb' with 'monitor.so' (C-extension)
and make it faster. See [Feature #16255] for details.

Monitor class objects are normal object which include MonitorMixin.
This patch introduce a Monitor class which is implemented on C
and MonitorMixin uses Monitor object as re-entrant (recursive)
Mutex. This technique improve performance because we don't need
to care atomicity and we don't need accesses to instance variables
any more on Monitor class.

1 files changed, 2 insertions, 0 deletions

diff --git a/ext/monitor/extconf.rb b/ext/monitor/extconf.rb
new file mode 100644
index 0000000000..78c53fa0c5
--- /dev/null
+++ b/ext/monitor/extconf.rb
@@ -0,0 +1,2 @@
+require 'mkmf'
+create_makefile('monitor')