build lib only in temp folder (disables any local intermediate files)

[da-h]

This PR moves the whole build process to the /tmp/pybison_X/ directory.

• Previously, some files would be created locally, i.e. in the folder the parser is defined in and only the actual C-compilation took place in the tmp directory.
• This, however, has led to some quirks: Letting bison / flex compile C-parser files locally has the disadvantage of polluting the local file structure, and deleting/moving files from a user folder is counterintuitive and possibly even problematic.
  • Due to a bug, some files would be processed in a local folder named ./tmp/pybison_X/.
  • When debugging using gdb, partially building locally (due to the previous two points), bisons debug symbols would mention files in the then wrong folder, making it impossible for gdb to show the respective lines it is currently in.

Both problems disappear by moving the whole build process (including bison / flex) to the temporary directory.

[da-h]

A small side-note: As no build files are created besides the PyBison-Parser definition, we can also omit the cleanup in the end of the buildLib-Method. What do you think?

[sbrodehl]

Hey @da-h, totally agree with your points. One thing I would like to check is if bison/flex overwrites already existing files. If I remember correctly we explicitly deleted some files before the subprocess is called, because something did not work right with already existing files.

[da-h]

Sure, I tested this at least for some cases and did not encounter any bugs, but I would not put my hand in the fire for this.

Easiest is probably to just remove the temporary directory? On the other hand, partial rebuilds may decrease compile time during development for larger parsers.