On Wed, 16 Apr 2008, Sérgio Durigan Júnior wrote:
In general a configure script should never modify CFLAGS. But flags
like -m64 that select a completely different ABI should better be put in
CC, not CFLAGS.
I will second the above statement.
Does that mean that CFLAGS is a variable only for the user? Well, let's
say that, for some strong reason, the configure is actually modifying
it. What would be the correct behaviour in this case? FYI, I'm talking
specifically about Python's build system, which uses 3 internal
variables ($BASECFLAGS, $OPT and $EXTRA_CFLAGS), but strangely ignores
the value of CFLAGS provided by the user. It's causing some troubles,
and we're trying to fix it. More information can be found at
http://bugs.python.org/issue1628484 .
That would seem to be a bug in Python's configure script. When it
comes to the variables listed at the tail of configure's --help
output:
Some influential environment variables:
CC C compiler command
CFLAGS C compiler flags
LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a
nonstandard directory <lib dir>
LIBS libraries to pass to the linker, e.g. -l<library>
CPPFLAGS C/C++/Objective C preprocessor flags, e.g. -I<include dir> if
you have headers in a nonstandard directory <include dir>
CPP C preprocessor
CXX C++ compiler command
CXXFLAGS C++ compiler flags
CXXCPP C++ preprocessor
F77 Fortran 77 compiler command
FFLAGS Fortran 77 compiler flags
FC Fortran compiler command
FCFLAGS Fortran compiler flags
user provided options should always be treated with respect and should
be honored in such a way that the user provided options will have most
useful effect. For example, if you add -I options to CPPFLAGS, then
the user-provided portion should be prepended so that the user can use
CPPFLAGS to override a default inclusion. For CFLAGS, the user
provided part should likely be appended so that the user can override
the defaults.
If a package is using Automake, then it is useful to take advantage of
AM_ prefixed variables in order to taint user-provided input as little
as possible.
Regardless, I seem to have built a 64-bit version of Python in an
environment which defaults to 32-bits by defining 'CC' rather than
'CFLAGS'.
Bob
======================================
Bob Friesenhahn
bfriesen@xxxxxxxxxxxxxxxxxxx, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
_______________________________________________
Autoconf mailing list
Autoconf@xxxxxxx
http://lists.gnu.org/mailman/listinfo/autoconf
