builder: Add missing dependency.

index-parser-c.c depends on index-parse.h being created first.
However without an explicit dependency, this is not done (and implicit
deps don't work because automake doesn't sufficiently understand OCaml
programs).

This fixes commit a4800e2d4fc50f372a8b626333c4fbb9b8ca9633.
builder: Add some generated files to CLEANFILES.

This updates commit a4800e2d4fc50f372a8b626333c4fbb9b8ca9633.
builder: Add dependency from index-parse.h to index-validate.

For some reason automake doesn't get this dependency right,
resulting in occasional build failures if yacc races the
rest of the build.
Version 1.25.6.