* gnu/packages/cpp.scm (fifo-map): New variable. * gnu/packages/patches/fifo-map-fix-flags-for-gcc.patch: New file. * gnu/packages/patches/fifo-map-remove-catch.hpp.patch: New file. * gnu/local.mk: Add new patch files. Signed-off-by: Ludovic Courtès <ludo@gnu.org>