Log Message:
*: Assume that the user has a C99-capable compiler.

A compiler that supports -std=c99 is required for
bootstrap, so it doesn't make sense to specify a c99
compiler everywhere in package makefiles.

At any rate, I would bet my entire life's savings that
this is a small fraction of the total number of packages
requiring c99.

Note that compilers that default to c89 but support c99
are still supported...