[CLN-list] CLN versus ia64

[Bruno Haible]

Ron Garret wrote:
> How do you force CLN to build in 64-bit mode?  None of the "obvious"  
> things I tried worked (e.g. ./configure --build=x86_64, CFLAGS=-m64  
> CXXFLAGS=-m64 ./configure).

The autoconf documentation [1], section "Preset Output Variables", says:

  "If an option affects multiple phases of the compiler, though,
   matters get tricky.  One approach to put such options directly into
   @code{CC}, e.g., @code{CC='gcc -m64'}.  Another is to put them into both
   @code{CPPFLAGS} and @code{LDFLAGS}, but not into @code{CFLAGS}."

The first approach:

$ export CC="gcc -m64" CXX="g++ -m64"
$ ./configure

The second approach:

$ export CPPFLAGS=-m64 CFLAGS="-O" CXXFLAGS="-O" LDFLAGS=-m64
$ ./configure

The third approach (a little safer than the second):

$ export CPPFLAGS=-m64 CFLAGS="-m64 -O" CXXFLAGS="-m64 -O" LDFLAGS=-m64
$ ./configure

All three work. Tested on Linux/x86_64.

Bruno


[1] http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=blob;f=doc/autoconf.texi;h=4e32e0873d1e0e37e2f04e5bb8eca81e0d36589a;hb=HEAD