Created attachment 639734 [details, diff] fix-configure-bashism.patch libticalcs2's configure.ac contains a Bashism (use of == operator with test built-in). Thus, configure emits an error when /bin/sh is not Bash. This doesn't cause the build to fail outright, but it may be causing misdetection of features. if test "x$build" == "x$host" ; then checking for the host compiler... ./configure: 16527: test: xx86_64-pc-linux-gnu: unexpected operator The attached patch removes the Bashism and allows sci-libs/libticalcs2-1.1.9 to configure without error when /bin/sh is Dash.