* dwarf2cfi.c: New file.

* dwarf2cfi.c: New file.
* dwarf2cfi.h: New file.
* dwarf2read.c (dwarf_frame_offset, dwarf_frame_size): New variables.
(dwarf_eh_frame_offset, dwarf_eh_frame_size): New variables.
(dwarf2_read_section): Change to non static.
(dwarf2_locate_sections): Add .debug_frame and .eh_frame section
recognition.
(FRAME_SECTION, EH_FRAME_SECTION): New define.
* elfread.c (elf_symfile_read): Add call of frame informations build.
* frame.h (frame_info): Add pointer to unwind_context.
* symfile.h (dwarf2_build_frame_info): Add declaration.
* gdbarch.sh (DWARF2_BUILD_FRAME_INFO): Add.
* gdbarch.h, gdbarch.c: Regenerate.
* Makefile.in: Add dwarf2cfi_h, dwarf2cfi.o
* x86-64-tdep.c (i386_gdbarch_init): Initialize target vector to
use debug frame info.