Make: $< is valid only in inference rule
When using bmake
w/o this patch, I get:
GEN data/valid-config-files/session.conf
usage: cp [-afpv] [-R [-H | -L | -P]] source ... dest
*** [data/valid-config-files/session.conf] Error code 1
make[3]: stopped in /build/build/test
1 error
This is because $<
is not expanded to the current target name. It is described here.