Add some error checking and reporting for writing upstream data
after import from yum.

Close files before deleting them for compatibility with MS-Windows

Use CSIDL on MS-Windows platforms instead of FHS paths.

Avoid use of non-standard %m printf conversion code.
Also switch to the more conventional ": <error>"
format allowing us to use perror() in more places.

Provide a program_name global variable as required by gnulib to
avoid the need for all programs that use librazor to do so.

Replace call to random() with the more portable rand() since we
don't have any need for a "good" random number generator.

Use fsync from gnulib for portability

Link to winsock2 under mingw (needed for ntohl).

Add an early include of config.h as required by gnulib

Remove another unnecessary include of sys/mman.h