doxygen 1.8.16 has a regression in how it handles an empty FILE_PATTERNS. The documentation claims that this causes a set of default patterns to be used and in other versions this is the case, but 1.8.16 incorrectly uses the empty set instead. For most affected software this just results in documentation being generated which doesn't actually document anything, but libsigrok fails to build entirely - see bug #698874 1.8.17 fixes this, but it was only just released and unfortunately it looks like this slipped through the cracks for long enough that the affected version got stabilized on most arches. There was nothing particularly obvious in the libsigrok compile failure that suggested doxygen was to blame. libsigrok bug: https://sigrok.org/bugzilla/show_bug.cgi?id=1422 doxygen bug: https://github.com/doxygen/doxygen/issues/7190
*** This bug has been marked as a duplicate of bug 698874 ***