People that did the "autotools update" failed to check the 'whys' of a certain hack. This results in gcc, instead of g++, being used for linking the library, leading to a broken library, as it's not linked to libstdc++. You can observe it i.e. as a failure to find the lib during imagemagick build. It's fixed by following the advice from automake info page: adding 'nodist_EXTRA_libfpx_la_SOURCES = dummy.cxx' in top level Makefile.am and eutoreconf.
Thanks for reporting, fixed without touching autotools, upstream should better rewrite them properly.
