By default, when make looks for the makefile, it tries the
following names, in order: `GNUmakefile', `makefile'
and `Makefile'.
Normally you should call your makefile either `makefile' or
`Makefile'. (We recommend `Makefile' because it appears
prominently near the beginning of a directory listing, right near other
important files such as `README'.) The first name checked,
`GNUmakefile', is not recommended for most makefiles. You should
use this name if you have a makefile that is specific to GNU
make, and will not be understood by other versions of
make. Other make programs look for `makefile' and
`Makefile', but not `GNUmakefile'.
If make finds none of these names, it does not use any makefile.
Then you must specify a goal with a command argument, and make
will attempt to figure out how to remake it using only its built-in
implicit rules. See section Using Implicit Rules.
If you want to use a nonstandard name for your makefile, you can specify
the makefile name with the `-f' or `--file' option. The
arguments `-f name' or `--file=name' tell
make to read the file name as the makefile. If you use
more than one `-f' or `--file' option, you can specify several
makefiles. All the makefiles are effectively concatenated in the order
specified. The default makefile names `GNUmakefile',
`makefile' and `Makefile' are not checked automatically if you
specify `-f' or `--file'.