On AIX 433 using the final version of xlc 126.96.36.199 the file autoconf.mk sets MOZ_GTK_LDFLAGS to contain "-Wl,-brtl". The option "-Wl" is invalid for this version of the compiler, so each time this option is passed to makeC++SharedLib_r a link error occurs.
MOZ_GTK_LDFLAGS is set by the output of `gtk-config --libs`. It looks like you're using a version of gtk+ that was compiled by gcc perhaps?
If you are using xlc to compile Mozilla and are using the GTK+ version from the AIX Linux Toolbox, then you need to make the following change to gtk-config (found in /opt/freeware/bin/gtk-config): Change the line: echo $libdirs -Wl,-brtl -lgtk -lgdk $my_glib_libs -lintl -lXext -lX11 -lm to: echo $libdirs -brtl -lgtk -lgdk $my_glib_libs -lintl -lXext -lX11 -lm The makeC++SharedLib script doesn't work well with commas in the options passed to it. A better workaround would be to create the libraries without using the makeC++SharedLib script.