I just updated my drm sources, ran autogen.sh, and then configure --prefix=/usr --enable-radeon-experimental-api --enable-nouveau-experimental-api Configure dies with: checking for alloca... yes ./configure: line 5129: syntax error near unexpected token `2.2' ./configure: line 5129: `LT_PREREQ(2.2)' A typo in configure.ac?
I can only find fd3ed34a2070fca3804baf54ece40d0bc2666226 which touched LT_PREREQ, and it added LT_PREREQ([2.2]) not LT_PREREQ(2.2) so I can't guess what the problem you saw was. Given that 18 months have passed without any more updates to this bug or reports of it happening to other people, I'm going to close it. Reopen if you are able to reproduce it still.
Just for records: Check the the comment bug 57018#c3
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