thread.c: fix indent

* thread.c (threadptr_local_aset): fix indent, remove unnecessary
  braces.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47002 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
string.c: rb_to_symbol

* string.c (rb_to_symbol): new function to convert an object to a
  symbol.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47003 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c, vm_method.c: avoid inadvertent pin-down

* thread.c (rb_thread_variable_set): get rid of inadvertent dynamic
  symbol pin-down.

* vm_method.c (obj_respond_to): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47004 b2dd03c8-39d4-4d8f-98ff-823fe69b080e