I've comitted some code which lets you select the GC implementation at runtime for debugging purposes. Basically, you can set the _INKSCAPE_GC environment variable to one of the following values:
* enable - use the normal garbage-collected allocator (default)
* debug - track additional debugging information[1] and detect certain types of heap corruption[2]
* disable - use standard malloc in place of the GC allocator[3]
_INKSCAPE_GC=disable mostly replaces the --disable-gc ./configure option, which has been removed.
-mental
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[1] for example, you can trace the path of references from an object to a GC root, to debug problems like an object mysteriously not getting collected
[2] it can't detect all corruption, but makes an honest effort
[3] it will leak memory fiercely, of course, since memory allocated with the standard allocator isn't automatically freed, but it's helpful for debugging sometimes