configure.in: indent

* configure.in (ac_cv_func___builtin_setjmp): adjust indent.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45512 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: restore flags

* configure.in (ac_cv_func___builtin_setjmp): should not skip
  flags restoration in RUBY_WERROR_FLAG by `break`.
  [ruby-dev:48086] [Bug #9698]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45513 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-04-04

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45514 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: get rid of clang fatal error

* configure.in (ac_cv_func___builtin_setjmp): get rid of a bug in
  clang 3.3 and 3.4, which __builtin_setjmp() causes fatal error
  in backend, linker error, or segmentation fault.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45515 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
eval_intern.h: VAR_INITIALIZED

* eval_intern.h (VAR_INITIALIZED): macro to suppress
  maybe-uninitialized warnings by gcc 4.7 and 4.8.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45516 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
signal.c: check stack overflow by SP

* signal.c (check_stack_overflow): raise SystemStackError if SP
  register and fault address is in the same page, on x86 linux.
  [EXPERIMENTAL]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45517 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Add libunwind support for Linux
Use backtrace_symbols_fd instead of backtrace_symbols

Conflicts:
	vm_dump.c
Dump x64 machine registers on sigsegv or sigbus

Conflicts:
	vm_dump.c
Clean up libunwind ifdef