Sorry, pasted the wrong snippet of rules.conf, this is the one adding the build-dep:
else
# build cross compiler
CROSS_BUILD_DEP := libc6-dev$(cross_lib_arch), zlib1g-dev$(cross_lib_arch), libmpfr-dev$(cross_lib_arch),
SOURCE_BUILD_DEP := gcc-$(BASE_VERSION)-source (>= $(GCC_VERSION)), gcc-$(BASE_VERSION)-source (<< $(NEXT_GCC_VERSION)),
Sorry, pasted the wrong snippet of rules.conf, this is the one adding the build-dep: (cross_ lib_arch) , zlib1g- dev$(cross_ lib_arch) , libmpfr- dev$(cross_ lib_arch) , VERSION) -source (>= $(GCC_VERSION)), gcc-$(BASE_ VERSION) -source (<< $(NEXT_ GCC_VERSION) ),
else
# build cross compiler
CROSS_BUILD_DEP := libc6-dev$
SOURCE_BUILD_DEP := gcc-$(BASE_