The macro $(SYSTEM_HEADER_DIR) is used in a double-quoted context, leading to nonportable "...`..."..."...`...", see <http://www.gnu.org/software/autoconf/manual/html_node/Shell-Substitutions.html>.Proposed untested patch. (I also haven't checked whether there are other instances of this issue in 'make install' code.)
If you or anybody can test this (better on an affected system, but even i686-pc-linux-gnu would be ok), ok for mainline and all affected release branches.
Paolo
