* SDCClabel.c: fixed bug #1638651: wrong linenumber presented in warning

* SDCClabel.c: fixed bug #1638651: wrong linenumber presented in warning
* src/asm.c: don't die if the file drfined in #line couldn't be opened
* src/SDCC.lex, src/SDCCglobal.h, src/SDCCicode.c, src/SDCCsymt.c,
  src/SDCCval.c: removed redundant definitions of currFname and mylineno;
  use filename in lineno instead.
* SDCCast.c: removed MSVC warning C4018: '==' : signed/unsigned mismatch,
  print the file name in ast_print()

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4578 4a8a32a2-be11-0410-ad9d-d568d2c75423