[Mesa-dev] Making makedepend an hard dependency?

[Luca Barbieri]

Currently makedepend is used by the Mesa Makefile-based build system,
but not required.

Unfortunately, not having it makes dependency resolution non-existent,
which is a source of subtle bugs, and is a rarely tested
configuration, since all Mesa developers likely have it installed.

Furthermore some idioms require dependency resolution to work at all,
such as making generated files depend on headers.

How about failing configure if it's absent?