Revert "Enforce C11 usage in nica"
Revert "Enforce C11 usage in nica"

This reverts commit eb9dfaec09431f8232539370e4e3cf9ca89b3aba.
The travis configuration is currently using an ancient version of Ubuntu with
a compiler from the stone age, 4.6.x, so we'll have to enable C11 after this
is addressed.

ikeydoherty/libnica,ikeydoherty/libthingamabob,ikeydoherty/libthingamabob,ikeydoherty/libnica,ikeydoherty/libnica,ikeydoherty/libthingamabob