* src/SDCCmem.c (allocGlobal): don't turn S_REGISTER storage class

* src/SDCCmem.c (allocGlobal): don't turn S_REGISTER storage class
to S_FIXED for pic16 port and when symbol is not in level 0,
allocate for S_REGISTER storage class and pic16 port, too,
* src/pic16/device.h: prototype for checkSym,
* src/pic16/device.c (pic16_dump_access, checkSym): NEW,
* (pic16_assignConfigWordValue): test the value and the mask to
validate that the value is suitable for the configuration word,
* src/pic16/glue.c (pic16_printIvalFuncPtr): use 'externs' to
collect extern declared symbols, don't emit symbol twice, check
first if symbol is in publics set first,
* src/pic16/main.c (_pic16_keywords[]): added keyword 'register',
* added command line '--fstack' which enables an experimental
feature for stack access, too buggy to be used yet...
* src/pic16/ralloc.c (pic16_accessregWithName): NEW,
* (pic16_allocDirReg): when register has storage class S_REGISTER
allocate in pic16_dynAccessRegs,
* device/include/pic16/pic18f????.h: modified configuration word
naming convention, words started as CONFIG0H but should be CONFIG1H

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3411 4a8a32a2-be11-0410-ad9d-d568d2c75423