Replace forbidden chars in more places in the GAS assembler writer.
Add support for .set and .weak on AVR.
Fix 64 bit negation on AVR.
Add cpu_capabilities to cpuinfo.pas and fixed some peephole optimizations.
Pass >4 byte parameters by reference.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26943 3ad0048d-3df7-0310-abae-a5850022a9f2
Added AVR support to fpc and root Makefile.
Rebuilt root Makefile.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26944 3ad0048d-3df7-0310-abae-a5850022a9f2
Fixed some bugs in the AVR RTL code.
Changed atmega code to use weak linking for interrupt handlers.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26945 3ad0048d-3df7-0310-abae-a5850022a9f2