Hmm, it looks like this has not been approved/applied, but I also
have not seen any NACK.
This does address an annoying (and hard for novices to understand)
roadblock for someone installing GCC manually. Can this go in?
Gerald
On Sat, 24 Aug 2013, FX wrote:
> ping
>
>
>> Given that I did not receive any feedback on my earlier email on this topic,
>> I would like to send this patch for RFC. I'm not expert at this
>> configury-stuff, so please try to comment on both the test proposed and my
>> actual implementation :)
>>
>> The idea is to find a patch which both catches probable issues early on for
>> most x86_64-linux users, yet does not make build more complex for our power
>> users. So, I propose to include a specific check in toplevel configure:
>>
>> The cumulative conditions I suggest, in order to make it as unobtrusive as
>> possible for current users, are:
>>
>> 1. if we build a native compiler,
>> 2. on x86_64-linux (and possible other x86_64 targets whose maintainers want
>> to opt in),
>> 3. and neither --enable-multilib nor --disable-multilib were passed
>>
>> then:
>>
>> a. we check that the native compiler can handle 32-bit, by compiling a test
>> executable with the "-m32" option
>> b. if we fail, we error out of the configure process, indicating that this
>> can be overriden with --{enable,disable}-multilib
>>
>> I suspect this might catch (at configure time) the large majority of users
>> who currently get stuck at stage 2 with the "gnu/stubs-32.h" error, while
>> being invisible to a large majority of the power users.
>>
>> So, what do you think?
>>
>> FXIndex: configure.ac
===================================================================
--- configure.ac (revision 201292)
+++ configure.ac (working copy)
@@ -2861,6 +2861,26 @@ case "${target}" in
;;
esac
+# Special user-friendly check for native x86_64-linux build, if
+# multilib is not explicitly enabled.
+case "$target:$have_compiler:$host:$target:$enable_multilib" in
+ x86_64-*linux*:yes:$build:$build:)
+ # Make sure we have a developement environment that handles 32-bit
+ dev64=no
+ echo "int main () { return 0; }" > conftest.c
+ ${CC} -m32 -o conftest ${CFLAGS} ${CPPFLAGS} ${LDFLAGS} conftest.c
+ if test $? = 0 ; then
+ if test -s conftest || test -s conftest.exe ; then
+ dev64=yes
+ fi
+ fi
+ rm -f conftest*
+ if test x${dev64} != xyes ; then
+ AC_MSG_ERROR([I suspect your system does not have 32-bit developement
libraries (libc and headers). If you have them, rerun configure with
--enable-multilib. If you do not have them, and want to build a 64-bit-only
compiler, rerun configure with --disable-multilib.])
+ fi
+ ;;
+esac
+
# Default to --enable-multilib.
if test x${enable_multilib} = x ; then
target_configargs="--enable-multilib ${target_configargs}"
