cvs commit: src/usr.bin/make Makefile main.c nonints.h var.c

[Harti Brandt]

On Wed, 4 Aug 2004, Ruslan Ermilov wrote:

RE>On Wed, Aug 04, 2004 at 12:25:10PM +0200, Harti Brandt wrote:
RE>[...]
RE>> Note also that you cannot do 'cd /usr/src/usr.bin ;
RE>> make SUBDIR="last leave"' anymore.
RE>> 
RE>What do you mean?  AFAIK, this never worked because SUBDIR
RE>was put as an environment variable into sub-makes, and
RE>{last,leave}/Makefile would be confused by thinking they
RE>have a non-empty SUBDIR (and then the ${PROG}: target and
RE>a subdir:: target from bsd.subdir.mk come to a conflict):

Well, the example was bad. This idiom was used in the X ports to
build parts of X only, for example, imake.

RE>
RE>$ /old/make SUBDIR="last leave" regress
RE>===> last
RE>"/usr/share/mk/bsd.subdir.mk", line 60: Inconsistent operator for last
RE>make: fatal errors encountered -- cannot continue
RE>*** Error code 1
RE>
RE>Stop in /usr/src/usr.bin.
RE>$ /new/make SUBDIR="last leave" regress
RE>===> last
RE>"/usr/share/mk/bsd.subdir.mk", line 60: Inconsistent operator for last
RE>"/usr/share/mk/bsd.subdir.mk", line 66: warning: duplicate script for target "last" ignored
RE>make: fatal errors encountered -- cannot continue
RE>*** Error code 1
RE>
RE>Stop in /usr/src/usr.bin.
RE>
RE>> AL>Does this also apply to environment variables (CFLAGS="foo bar" make)?
RE>> 
RE>> No. Environment variables have lowest priority - command line variables
RE>> and makefiles override them. But you should be able to say
RE>> CFLAGS="foo bar" make -E CFLAGS to move up CFLAGS in the priority list.
RE>> 
RE>Uh no.  ``make CFLAGS="foo bar"'' won't *work* because CFLAGS+='s won't
RE>DTRT, since command-line variables still take precedence over globals:
RE>
RE>$ cat makefile
RE>FOO=	foo
RE>FOO+=	bar
RE>all:
RE>.if ${FOO} != "foo bar"
RE>	@echo impossible
RE>.endif
RE>$ make FOO=ick
RE>impossible

This is the intented behaviour. 'Work' means, that CFLAGS gets passed to
all sub-makes and will not be overridden there. This does not mean that
this mechanism makes sense for CFLAGS.

RE>This commit isn't changing much, and the change is really natural.
RE>All it does it to ensure that once FOO is specified as a command
RE>line variable, it stays the command-line type variable in sub-makes.
RE>The other semantics is not touched.

Well, you can say 'make CFLAGS=-O' and that will use -O (and only -O) 
in all sub-makes. This is different from previous behavious where -O
was not passed to sub-makes. For CFLAGS this doesn't make much sense,
because CFLAGS are usually modified in Makefiles for a good reason, but
it should enable you to do 'make CC=icc' or 'make WARNS=9' or 'make COPTS=-O5'
and be sure that is used by all sub-makes. (Note: this breaks
i4b which uses COPTS to mean CFLAGS).

Most, if not all, of our Makefiles are careful to use += or ?= to not
clobber existing values, so this change does help more with makefiles
from external sources that contain a big hierarchy of Makeflags each one
containing

OPTFLAGS= -O
CC= gcc
...

harti