reduce rb_mutex_t size from 80 bytes to 72 bytes on 64-bit
We can use existing RVALUE flags to avoid adding a 4-byte
integer to store a boolean flag. This integer cost us 8 bytes
due to default (lack of) struct packing on x86-64
thread_sync.c (MUTEX_ALLOW_TRAP): define as FL_USER1
(struct rb_mutex_struct): remove allow_trap
(rb_mutex_lock): adjust for flag check
(rb_mutex_allow_trap): adjust for flag set/unset
reduce rb_mutex_t size from 80 bytes to 72 bytes on 64-bit
We can use existing RVALUE flags to avoid adding a 4-byte
integer to store a boolean flag. This integer cost us 8 bytes
due to default (lack of) struct packing on x86-64
(struct rb_mutex_struct): remove allow_trap
(rb_mutex_lock): adjust for flag check
(rb_mutex_allow_trap): adjust for flag set/unset
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58608 b2dd03c8-39d4-4d8f-98ff-823fe69b080e