amunits: MsgBox unit renamed to AMsgBox, conflicts with FV

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28566 3ad0048d-3df7-0310-abae-a5850022a9f2
Amiga: rtl-console and fv now builds for classic Amiga. It probably still nukes badly though, due to problems in the age-old AmUnits interface units. To be fixed soon.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28567 3ad0048d-3df7-0310-abae-a5850022a9f2
* fixes reference handling for arm thumb and ldrh, not perfect yet

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28568 3ad0048d-3df7-0310-abae-a5850022a9f2