eaglemode: Don't build on Hydra

The build can loop forever generating an infinite amount of log data,
filling up Hydra's disk:

gcc -Llib -L/nix/store/0xb56zcqii361ksknjwh9m853zb886yq-glib-2.46.0/lib -L/nix/store/48hidn50ynp4kk4lsfzjvkbg30yhfgaq-gdk-pixbuf-2.32.0/lib -L/nix/store/dfxv36h389wvkblv3qjgfs2zyklgdlp4-cairo-1.14.2/lib -L/nix/store/wy5f8alalh681jbq3hjh93rcc87d6nch-freetype-2.5.4/lib -L/nix/store/b6kaw1i6fadgssn38xv4rkfsa7q70rfa-fontconfig-2.11.1/lib -L/nix/store/9n1ynjgcmxlhz75l1mnd07zb0pkgvpzi-gtk+-2.24.28/lib -L/nix/store/782agz0g2hn4n02a23vsaly2sr1kwxhd-pango-1.38.0/lib -L/nix/store/ljalzp7gjv76bqbxm6ia3vmw3vhfambr-atk-2.18.0/lib -L/nix/store/pkssk6q14y17q9jji5q5gk70sf3hz6hs-poppler-glib-0.34.0/lib obj/emPdfServerProc.o -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lgdk_pixbuf-2.0 -lpangoft2-1.0 -lpango-1.0 -lfontconfig -lfreetype -lpoppler-glib -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lcairo
 -lm -o lib/emPdf/emPdfServerProc
/nix/store/kxf1p7l7lgm6j5mjzkiwcwzc98s9f1az-binutils-2.23.1/bin/ld: cannot find -lcairo

collect2: error: ld returned 1 exit status
---
Building emPdf failed, but that project is not so essential.
So if you don't know how to solve the problem, then you could
continue the overall building now, and live without the features
the project provides. Continue? [y(es)/n(o)/a(lways)]: Use of uninitialized value $ln in pattern match (m//) at make.pl line 626.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 629.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 632.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 636.
Say yes, no or always: Use of uninitialized value $ln in pattern match (m//) at make.pl line 626.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 629.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 632.
Use of uninitialized value $ln in pattern match (m//) at make.pl line 636.
...

@viric

http://hydra.nixos.org/build/26505594