Help with Makefile

[Root Boy Jim]

? From: Micky Liu <micky at cunixc.cc.columbia.edu>

? I am trying to build a Makefile for sources that have to be built
? for different architectures.  So let's say I have my sources at
? the root and I want to place the objects in their subdirectories
? under the root like:

? /src

? /src/vax

? /src/sun3

? /src/sun4

? But I only want to keep one Makefile in the my /src directory.
? I have already made a method to determine the architecture and
? then it invokes itself with the proper flags.  The problem is
? that I cannot seem to get the implicit rules to work anymore.

? Let's say I'm on the vax, and I type make.  It figures out that
? I'm on the vax and then IT does something like:

? make CCFLAGS=-DVAX

? but when it actually gets to a target it says that it doesn't know
? how to make vax/hello.o, or omething like that.  I ended up making
? explicit rules for each source file, but would really like to be
? able to use the implicit rules...

? Any clues, or other methods of maintaining a single source tree for
? different architectures?

This is just a WAG, I haven't tried it. Code you Makefile as if you were
in the subdirectory. Then add the following entry at the beginning:

vax sun3 sun4 whatever:
	(cd $@; make -f ../Makefile all)

Where the target `all' builds your program. Just type `make vax' to
build the program for the vax. The targets for clean and install are
more complex.

Another way to do it is by using the `arch' command.

all clean install:
	(cd `arch`; make -f ../Makefile ARCH=-D`arch | tr a-z A-Z` real$@)

Of course, there is also the VPATH variable, which may or may not work.

? Thanx!

? Micky Liu

?   arpa: micky at cunixc.cc.columbia.edu
?   uucp: ...!rutgers!columbia!cunixc!micky
? bitnet: malua at cuvmc

	Root Boy Jim and
	the GNU Bohemians