They were never really needed and caused troubles in the presence of
circular module dependencies as reported by
Danny Milosavljevic <dannym@scratchpost.org> at
<https://lists.gnu.org/archive/html/guix-devel/2016-11/msg00144.html>.
* gnu/packages/cross-base.scm (xgcc-mips64el, xgcc-xtensa, xgcc-armhf):
Remove.
* gnu/packages/firmware.scm (ath9k-htc-firmware)[native-inputs]: Use
'cross-gcc' instead of XGCC-XTENSA.
* gnu/packages/firmware.scm (ath9k-htc-firmware)[source](file-name): New
field.
* gnu/packages/gnunet.scm (guile-gnunet)[source](file-name): New field.
* gnu/packages/guile.scm (guile-next)[source](file-name): New field.
(guile-minikanren)[source](file-name): New field
(guile-gdbm-ffi)[source](file-name): New field.
* gnu/packages/ssh.scm (guile-ssh)[source](file-name): New field.