* src/SDCCglobl.h: ensure that PATH_MAX >= 2048 to guarantee

* src/SDCCglobl.h: ensure that PATH_MAX >= 2048 to guarantee
  cmdLine buffers (used when calling sdcpp...) are large enough
  (MAX_PATH=256 truncates arguments leading to system halts when
  used in MinGW...)
* src/pic16/gen.c (pic16_sameRegs): relaxed size criterion
* (genUminus): rewritten to for efficiency
* (genNearPointer[GS]et): enforce reloading of FSR0 (was still
  used uninitialized in some cases)
* (genCast): upcasting a 16bit int to a 24bit GPOINTER may not
  copy the third byte from the int -- now assumes 0x80 (data memory)
* src/pic16/genarith.c (pic16_genPlus): fixed bug when swapping
  operands (genAddLit expects the iCode's operands to swapped as
  well), fixed leftover bytes (crashed for short left operands)
* (pic16_genMinusDec): performance improvements, removed false
  PIC14 emitSKPNCs
* (pic16_genMinus): fixed to cope with differently sized operands
* src/pic16/glue.c (pic16_glue): added new banksel optimization
  for --obanksel > 1
* src/pic16/pcode.c: implemented (first phase of) banksel optimization
* src/pic16/graph.[ch]: implementation of directed graphs, used by
  new banksel optimization
* src/pic16/pcoderegs.c (pCodeRegMapLiveRangesInFlow): prevented
  analysis for temporary registers (segfaults...)
* src/pic16/peeph.def: added rule

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3640 4a8a32a2-be11-0410-ad9d-d568d2c75423