Compiler/language update, compiler edit 828: Migrate the various RUN-time compatible enhancements added so far to the 6.5 compiler, back to 6.4 so as to make them available to developers working on library routines that might need to be compiled in the 6.4 environment.

The new features are:

•   DEFSTRUCT can now include MAP1 (edit 821, also released with 6.5.1603)

•   Assignment shortcut operators |= and &= (edit 822, 6.5.1605)

•   XPUTARG @argname for functions (edit 825, 6.5.1607)

•   XPUTARG{SBX} @argname for SBXs (edit 828, 6.5.1608)

Note that all of these are purely coding conveniences and do not affect the RUN file, so there are no backwards compatibility issues.