Upgrade to gcc 7.4.0 and build gcc and gfortran without isl

[vbraun]

This ticket upgrades to gcc 7.4.0 and builds gcc and gfortran without isl.

Tarball: ​ftp://ftp.mirrorservice.org/sites/sourceware.org/pub/gcc/releases/gcc-7.4.0/gcc-7.4.0.tar.xz

The upgrade fixes the issue that gcc 7.2.0 does not build on newer systems that have glibc 2.28:

This issue looks like ​https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85835

[gcc-7.2.0] libtool: compile:  /mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/var/tmp/sage/build/gcc-7.2.0/gcc-build/./gcc/xgcc -B/mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/var/tmp/sage/build/gcc-7.2.0/gcc-build/./gcc/ -B/mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/x86_64-pc-linux-gnu/bin/ -B/mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/x86_64-pc-linux-gnu/lib/ -isystem /mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/x86_64-pc-linux-gnu/include -isystem /mnt/disk/home/buildslave-sage/slave/binary_pkg/build/source/SageMath/jc4b6yulaujayb9sr94ia88eourzeq/local/x86_64-pc-linux-gnu/sys-include -DHAVE_CONFIG_H -I../../../src/libatomic/config/x86 -I../../../src/libatomic/config/posix -I../../../src/libatomic -I. -Wall -Werror -pthread -g -O2 -MT cas_16_1_.lo -MD -MP -MF .deps/cas_16_1_.lo.Ppo -DN=16 -DIFUNC_ALT=1 -mcx16 -c ../../../src/libatomic/cas_n.c -o cas_16_1_.o >/dev/null 2>&1
[gcc-7.2.0] ../../../../src/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc:157:10: fatal error: sys/ustat.h: No such file or directory
[gcc-7.2.0]  #include <sys/ustat.h>
[gcc-7.2.0]           ^~~~~~~~~~~~~
[gcc-7.2.0] compilation terminated.
[gcc-7.2.0] make[10]: *** [Makefile:523: sanitizer_platform_limits_posix.lo] Error 1

The reason for building without isl is that sage now includes isl as an optional package, so we should build gcc without it for the sake of consistency (see discussion in #26735).

Related tickets: #26735, #27016.

[Konrad127123]

The attached commits upgrade gcc to 7.4, which should fix this and make that the fix for #26735 redundant.

I've also disabled building gcc with isl, since that is now an optional package in sage (see also discussion in #26735). If isl ever becomes a standard package, gcc should be made to depend on it, the --disable-isl line can be removed and the hacks for gmp and friends when building gcc should also be added for isl.

I have not tested this set of changes yet.

---

New commits:

​6f07d2f	Update gcc to 7.4
​62d8e3b	isl patch is in gcc 7.4
​299a61a	Disable isl when building gcc to avoid inconsistently building gcc with sage's optional isl package. See also #26735.

[Konrad127123]

Update: with the attached changes, gcc now builds again on my computer (and #26735 does not come back).

(Later in the build process (but only if I build gcc), I get the following error when trying to build givaro:

-----------------------------------------------
checking gmp.h usability... yes
checking gmp.h presence... yes
checking for gmp.h... yes
checking for GMP library... yes
checking gmpxx.h usability... no
checking gmpxx.h presence... yes
configure: WARNING: gmpxx.h: present but cannot be compiled
configure: WARNING: gmpxx.h:     check for missing prerequisite headers?
configure: WARNING: gmpxx.h: see the Autoconf documentation
configure: WARNING: gmpxx.h:     section "Present But Cannot Be Compiled"
configure: WARNING: gmpxx.h: proceeding with the compiler's result
configure: WARNING:     ## --------------------------------------------------- ##
configure: WARNING:     ## Report this to http://github.com/linbox-team/givaro ##
configure: WARNING:     ## --------------------------------------------------- ##
checking for gmpxx.h... no
your GMP does not have c++ support. Compile GMP with --enable-cxx
********************************************************************************

My suspicion is that this failure is unrelated, and should be a separate issue.)

[Konrad127123]

Update: I tried bulding sage again with the attached patch. It worked, and all tests passed with make testlong. The givaro issue above was most likely a case of running out of diskspace.

[embray]

Retarging tickets optimistically to the next milestone. If you are responsible for this ticket (either its reporter or owner) and don't believe you are likely to complete this ticket before the next release (8.7) please retarget this ticket's milestone to sage-pending or sage-wishlist.

[Konrad127123]

Retarging tickets optimistically to the next milestone. If you are responsible for this ticket (either its reporter or owner) and don't believe you are likely to complete this ticket before the next release (8.7) please retarget this ticket's milestone to sage-pending or sage-wishlist.

This patch is ready to go. It just needs someone to review it :).

[embray]

It looks like #27016 will likely conflict with this. Perhaps I could combine the two (especially if my ticket is reviewed)?

[Konrad127123]

Replying to embray:

It looks like #27016 will likely conflict with this. Perhaps I could combine the two (especially if my ticket is reviewed)?

I don't have enough knowledge of the build system to feel comfortable reviewing #27016. I have no objection to you combining the two: cherry-pick 6f07d2f and 62d8e3b, then add --without-isl to the configure options for both gcc and gfortran (I just noticed gfortran is built from the same source as gcc, so it should also get the --without-isl option for the same reason; my patch currently omits this.)

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​2436a0e

Disable isl when building gfortran to avoid inconsistently building gfortran with sage's optional isl package.

[Konrad127123]

I've now also added --without-isl to the configure script for gfortran. I've not tested the gfortran part. I've not merged with #27016.

[slelievre]

Changing the ticket summary from "The gcc package doesn't build with new gcc" to "Upgrade to gcc 7.4.0 and build gcc and gfortran without isl".

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​83dfeb9	Update gcc to 7.4
​8154dda	isl patch is in gcc 7.4
​efc63b8	Disable isl when building gcc to avoid inconsistently building gcc with sage's optional isl package. See also #26735.

[Konrad127123]

Patch now rebased on top of #27016.

[embray]

Ticket retargeted after milestone closed (if you don't believe this ticket is appropriate for the Sage 8.8 release please retarget manually)