independent of the actual input from the file. Change macro handling
to use the new input stack.
Fixed an error in FreeIf: If an unexpected .ENDIF was reached, the
assembler started an endless loop printing error messages.
git-svn-id: svn://svn.cc65.org/cc65/trunk@24 b7a2c559-68d2-44c3-8de9-860c34a00d81