* src/port.h: added TARGET_MCS51_LIKE

* src/port.h: added TARGET_MCS51_LIKE
* src/SDCCpeeph.c (labelIsUncondJump): new, added, other targets could
  take advantage of it too
* src/z80/gen.c (genIpush): push b, d or h directly instead of using a,
  (shiftR2Left2Result): Optimized: don't check shifting by 0
* src/z80/peeph-z80.def,
* src/z80/peeph.def: whole set of new rules by Philipp Krause with some
  modifications, see patch 1700823

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4786 4a8a32a2-be11-0410-ad9d-d568d2c75423