Hello, I just tried to compile notmuch with an oldish compiler, and that failed (if the compiler is indeed too old, then at least the error message should be more helpful): % ./configure --prefix=$HOME/stow/notmuch [...] Sanity checking C compilation environment... OK. Sanity checking C++ compilation environment... OK. Reading libnotmuch version from source... *** Error: Reading lib/notmuch.h failed. Please try running configure again in a clean environment, and if the problem persists, report a bug. % cc -g -O2 _libversion.c -o _lib In file included from _libversion.c:2: lib/notmuch.h:858: error: wrong number of arguments specified for ‘deprecated’ attribute lib/notmuch.h:915: error: wrong number of arguments specified for ‘deprecated’ attribute lib/notmuch.h:1011: error: wrong number of arguments specified for ‘deprecated’ attribute lib/notmuch.h:1048: error: wrong number of arguments specified for ‘deprecated’ attribute % gcc --version gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-16) Copyright (C) 2010 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Cheers, Justus