ci: Use correct variable to designate C++ compiler

[hebasto]

Setting the CC variable does not affect the choice of a C++ compiler. CXX does.

On the master branch (c36f1f0), CI tasks, which are supposed to compile using a non-default compiler (e.g., clang), actually are configured to use the default compiler. For example, https://api.cirrus-ci.com/v1/task/5042259930906624/logs/test.log:

+ clang -v Debian clang version 11.0.1-2 Target: x86_64-pc-linux-gnu ... Build Options: with benchmarks = yes with tests = yes enable clmul fields = yes CXX = g++ -std=c++11 ... 

[maflcko]

Looks like CI didn't run?

[maflcko]

@hebasto Maybe rebase for the CI to run?

[hebasto]

Maybe rebase for the CI to run?

Rebased.

[maflcko]

 /usr/bin/ld: cannot find /usr/lib/llvm-14/lib/clang/14.0.6/lib/linux/libclang_rt.ubsan_standalone-x86_64.a: No such file or directory /usr/bin/ld: cannot find /usr/lib/llvm-14/lib/clang/14.0.6/lib/linux/libclang_rt.ubsan_standalone_cxx-x86_64.a: No such file or directory 

[maflcko]

Suggested change

	CXX: clang++
	CXX: clang++ -gdwarf-4

This is temporarily needed for valgrind. See the error:

+ valgrind --error-exitcode=42 ./test 1 ==4991== Memcheck, a memory error detector ==4991== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al. ==4991== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info ==4991== Command: ./test 1 ==4991== ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x23 ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x25 ### unhandled dwarf2 abbrev form code 0x23 ==4991== Valgrind: debuginfo reader: ensure_valid failed: ==4991== Valgrind: during call to ML_(img_get) ==4991== Valgrind: request for range [822865493, +4) exceeds ==4991== Valgrind: valid image size of 29291312 for image: ==4991== Valgrind: "/tmp/cirrus-ci-build/test" ==4991== ==4991== Valgrind: debuginfo reader: Possibly corrupted debuginfo file. ==4991== Valgrind: I can't recover. Giving up. Sorry. ==4991== 

[maflcko]

Same below

[hebasto]

Thanks! Done.

[maflcko]

+ wine ./test it looks like wine32 is missing, you should install it. as root, please execute "apt-get install wine32:i386" wine: failed to open "./test": c0000135 

[maflcko]

Concept ACK. Haven't reviewed. I presume the qemu-s390x failure will fix itself once debian stable is rolled.

[maflcko]

cc @theuni as potential reviewer

[theuni]

Whoops! Nice catch.

Concept ACK. Looks like there are still a few legit c-i issues to fixup.

[sipa]

utACK e051a7d