I noticed this when reading the Readme.txt file found in the C:\Program Files\PureBasic\Library SDK\ folder that it says
III. Using LccWin32 to develop PureLibraries
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First, you have to get a recent version LccWin32 (version 3.2 and above). Lcc32 is
a freeware C compiler, with an integrated IDE which produce very good code.
According to the license on the authors website it says:
License:
This software is not freeware, it is copyrighted by Jacob Navia. It's free for non-commercial use, if you use it professionally you have to have to buy a licence.
Not sure if this is a typo or of the license have been updated, but I think Fred should have a look at this to avoid any legal problems.