fix the WIN32 target

from Antoine Leca, on pcc-list
add missing ;;
define 0 for unused, for CRTI and CRTN like the other CRT files
strap handles the 0 case already
For CRTI, use 0 for unused
update ccconfig.h file definitions to [hopefully] match the
schema of the cc front end
new date 20141219
avoid using $(EXEEXT) in manpage names

fixes PCC-507 by Antoine Leca
use const for warning function prototypes (reduce warnings)

fixes PCC-506 by Antoine Leca
new date 20141223
from discussion on pcc-list, add support for *-*-linux-musl target

cc.c

- split DYNLINKER into
  DYNLINKARG defaults to "-dynamic-linker" but can be overridden
  DYNLINKLIB defaults to NULL or should be specified in ccconfig.h

- parse -mbig-endian, -mlittle-endian, -msoft-float and -mhard-float
  for mips and arm

- add a PCC_SETUP_LD_ARGS hook

os/linux/ccconfig.h
- provide handling for musl target, which uses different dynamic
  linker per arch, per endian and per floating type

os/*/ccconfig.h

- fix up DYNLINKARG and DYNLINKLIB generally

configure
configure.ac

- detect *-linux-musl*, and pass -DUSE_MUSL to build
add -### flag in cc front end. This is like -v except that the
commands are not run, and arguments will be quoted if they
contain non alphanumeric characters
fix PE/COFF target

from Antoine Leca in PCC-509
further fixes for WIN32 target using MinGW runtime

from Antoine Leca in PCC-509
update win32 config for updated cc, when using MinGW runtime

from Antoine Leca in PCC-509
new date 20141225
Add i86, from Alan Cox.
Updates for i86, from Alan Cox.
Fix bug when generating 16-bit mul, as reported by Alan Cox on pcc-list.
new date 20141227