Filter -Ymacro-expand from build compiler

Filter both -Xsource and -Ymacro-expand options from the build compiler.

The two options are needed to put the presentation compiler in compatibility
mode, but they should not make it to the build compiler. (2.10 does replies
with `bad option:-Xsource`, for example)

An annoying fix *en-passant*, regarding missed error reporting in compiler initialization.