E.g. CXX src/nix-log2xml/log2xml.o CC src/bsdiff-4.3/bsdiff.o GEN scripts/nix-channel LD src/libmain/libnixmain.so
This is useful when you do: foo_SOURCES := $(wildcard *.cc) foo.cc where foo.cc is a generated file. In this case, if foo.cc already exists, you get foo.cc twice in foo_SOURCES, leading to a link error.
This makes it easier to use with "git subtree".