+@unnumberedsubsec Flex-2.5.4a and gcc-3.1.x
+
+Flex 2.5.4a does not produce g++-3.1.1 compliant C++ code. To compile
+LilyPond with gcc-3.1.1 you may do:
+
+@example
+ CONF=gcc-3.1 ./lexer-gcc-3.1.sh
+ CPPFLAGS=-I$(pwd)/lily/out-gcc-3.1 CC=gcc-3.1 CXX=g++-3.1 \
+ ./configure --enable-config=gcc-3.1
+ CONF=gcc-3.1 ./lexer-gcc-3.1.sh
+ make conf=gcc-3.1
+@end example
+
+This assumes that the GCC 3.1 binaries are called gcc-3.1 and g++-3.1.
+Note that this is @strong{not} fixed in Debian/unstable for flex <=
+2.5.4a-26.
+
+@unnumberedsubsec Linux-2.4.0, Guile-1.4 --with-threads
+
+There's a bug in certain kernels around version 2.4.0, that is
+triggered when using Guile 1.4 compiled with pthreads. You'll see
+random segmentation fault crashes of LilyPond. Upgrade to a newer
+version of Linux. If you can't do that, you may try to recompiling
+Guile without threads (YMMV):
+
+@example
+ guile-1.4$ ./configure --without-threads; make all install
+@end example
+
+@unnumberedsubsec OpenBSD
+
+@itemize @bullet
+@item By default, gcc on OpenBSD doesn't include
+@file{/usr/local/include} and @file{/usr/local/lib} in the system
+paths. Depending upon where/how you installed kpathsea and other
+libraries, you may need to refer to the section ``Linking to
+kpathsea''.
+
+@end itemize
+