1) There is no way to do that in portable Make syntax (ephemient's answer will work only with GNU Make)
2) There is no way to do that using Automake either. (Although the feature should not be too hard to implement by someone who need it...)
Personally I don't really see the advantage to using
foo_SOURCES = subdir/{foo,bar,baz}.c
over
foo_SOURCES = \
subdir/foo.c \
subdir/bar.c \
subdir/baz.c
I find the former is more cryptic, and it is not grepable (e.g. to answer the question "which Makefile
mentions foo.c
?").