irop: Remove unused NULL_FUNC.
tr: Remove stale declarations.
lower: Remove unused idents.
irdump: Remove the read-to-write-self variable dump_file_filter_id.
ir_prog: Remove unused ip_outedges.
ir_prog: Remove unused callgraph analysis info.
ir_prog: Update documentation.
ir_graph: Remove unused callgraph analysis info.
all: Simplify bool ? true : false to just bool.
all: Use MAX.
all: Use MIN.