Kevin Ryde wrote:
Balint Joo <bj@xxxxxxxxxxx> writes:
In my case the answer is that I am trying to compile a parallel program, which needs a special compiler (mpcc). However in order to run the output of mpcc, I need to be in a batch queue. Outwith the batch queue I cannot run executables compiled with the parallel environment.
A somewhat similar situation arises on sparc64 solaris, where executables in the 64-bit ABI can't run if the kernel is in 32-bit mode. The compiler can create them, but they can't run. In gmp we recommended what Guido said, fake up a --build to make it look like a cross compile. --build=none for instance, since gmp (and I would guess a lot of packages) doesn't pay attention to the actual build system type.
Indeed! I had been cautious since some toolchains do actually compile some tools on the build system but in fact they can get away with plain stdc code which they try to stick with just for the reason to be extra portable. No optimizations for the specific platform in there.
To be a bit sure, I've been grepping a bit around. First,
autoconf macro dir - nothing, nothing goes to test \$build
there. In aclocal, we can find a single valid reference to
\$build - in libtool.m4 as
if test x"$host" != x"$build"; thenThe only likely candidate that I can think of, well, that's a package with a compiler-compiler - and gcc is the best candidation I can think of in this area since I do know it does that `canadian cross` (or what its called) with compiler a compiler-compiler on the fly to compiler the compiler for the host system that can compile a binrary for the target system (phew!) - anyway, let's grepp it:
boehm-gc/configure:case "$build_alias" in boehm-gc/configure:case "$build_alias" in gcc/configure:case "$build_alias" in gcc/configure:if test $host != $build; then gcc/configure:case $build in gcc/configure:for machine in $build $host $target; do gcc/configure:if test x$host = x$build gcc/configure: FORBUILD=../$build_alias gcc/configure:if test x$build != x$host gcc/configure:if test x$host != x$build gcc/configure.in:case $build in gcc/configure.in:for machine in $build $host $target; do gcc/configure.in: FORBUILD=../$build_alias gcc/configure.in:if test x$build != x$host gcc/configure.in:if test x$host != x$build gcc/configure.in: str3=" on a $build system" libf2c/configure:case "$build_alias" in libf2c/configure:if test $host != $build; then libffi/configure:case "$build_alias" in libffi/configure:if test $host != $build; then libiberty/configure:case "$build_alias" in libjava/configure:case "$build_alias" in libjava/configure:case "$build_alias" in libobjc/configure:case "$build_alias" in libobjc/configure:if test $host != $build; then libstdc++-v3/configure:case "$build_alias" in libstdc++-v3/configure:if test $host != $build; then libstdc++-v3/configure:if test -n "$with_cross_host" || test x"$build" != x"$hos t"; then libstdc++-v3/configure: if test -n "$with_cross_host" && test x"$build" != x"$w ith_cross_host"; then libstdc++-v3/configure:if test x"$build" = x"$host" && test -z "$with_cross_host "; then libstdc++-v3/configure.in:if test -n "$with_cross_host" || test x"$build" != x"$ host"; then libstdc++-v3/configure.in: if test -n "$with_cross_host" && test x"$build" != x "$with_cross_host"; then zlib/configure:case "$build_alias" in zlib/configure:if test $host != $build; then
Now, that looks like a lot, does it ?
However, most of the "case $build_alias in" turn out to be from the following snippet copy-n-pasted around:
build_alias=$build case "$build_alias" in NONE) case $nonopt in NONE) build_alias=$host_alias ;; *) build_alias=$nonopt ;; esac ;; esac
For our interest, let us cut out (1) all references like $build != $host (2) cut out case-check for $build = NONE as above as we result, we are left with:
gcc/configure:case $build in gcc/configure-vax-*-*) gcc/configure: FORBUILD=../$build_alias
Now finally, we have a single reference in the world to the actual value of $build - what's it like? Well, here you are:
case $build in
vax-*-*)
if test x$GCC = xyes
then
stage1_cflags="-Wa,-J"
else
stage1_cflags="-J"
fi
;;
powerpc-*-darwin*)
# The spiffy cpp-precomp chokes on some legitimate constructs in GCC
# sources; use -no-cpp-precomp to get to GNU cpp.
# Apple's GCC has bugs in designated initializer handling, so disable
# that too.
stage1_cflags="-no-cpp-precomp -DHAVE_DESIGNATED_INITIALIZERS=0"
;;
esac
AC_SUBST(stage1_cflags)well, one may guess that it is really the only single reference in the world.... cheers, -- guido http://AC-Archive.sf.net GCS/E/S/P C++/++++$ ULHS L++w- N++@ d(+-) s+a- r+@>+++ y++ 5++X-
