Jack Mitchell reported that Denzil fails to build m4 on his host distro that uses eglibc 2.16. eglibc 2.16 dropped the implmentation of gets(), and so recipes that use this function call need to be patched. Khem Raj developed a series of patches to fix this, which at this time have not yet been merged into poky master.
Moving target milestone to 1.2.2 since this version of eglibc is brand new and our tested, released host distros are not using it yet.
Patches are now in sgarman/denzil-next
Fixed in oe-core and poky denzil branches as of: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?h=denzil&id=07f304f4e28dc596b1420ae1cb6607d7706108e4