Include config.h and time.h.

Include config.h and time.h.
Declare extern data and functions.
(file_data): Move definition from w32heap.c.
(_start): Add debug hook for when profiling.
Spoof executable name when using profilers.
Invoke sbrk immediately when undumped.
(unexec): Print error messages when input and output dump files
cannot be opened.
Reset header checksum.
(open_input_file, open_output_file): Return status instead of aborting.
(get_section_size): Handle different linkers.
(find_section, rva_to_section): New functions.
(get_section_info) [SEPARATE_BSS_SECTION]: Make code for using
a separate .bss section conditional.
Use my_begbss and my_endbss to determine .bss size by default.
Look for Emacs data in EMDATA section.