[PATCH 1/2] README: bump minimum required clang/llvm version

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

We no longer have a way to build with the minimum required clang/llvm version
stated in the README on the gitlab CI loop, since we dropped the Debian Jessie
container that had Clang 3.5.0.

Bump the minimum required Clang/LLVM to the one used in the oldest production
FreeBSD version (13.2 currently), as that's the main reason I care to maintain
Clang/LLVM support, and as far as I know FreeBSD is the only production
deployment of Xen built with Clang/LLVM.

Purge the build jobs for non-supported Clang versions from Gitlab CI.  Note the
.dockerfiles for the respective distros are explicitly not adjusted to drop the
install of the clang packages, or else those jobs would start to fail on older
Xen branches.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
I'm willing to consider older versions, but there needs to be a reason (iow:
use-case) for considering those, as maintaining support for older toolchains is
a burden.
---
 README                          |  2 +-
 automation/gitlab-ci/build.yaml | 45 ---------------------------------
 2 files changed, 1 insertion(+), 46 deletions(-)

diff --git a/README b/README
index c8a108449e29..5fe52cc7a932 100644
--- a/README
+++ b/README
@@ -41,7 +41,7 @@ provided by your OS distributor:
         - GCC 4.1.2_20070115 or later
         - GNU Binutils 2.16.91.0.5 or later
         or
-        - Clang/LLVM 3.5 or later
+        - Clang/LLVM 14.0.0 or later
       - For ARM 32-bit:
         - GCC 4.9 or later
         - GNU Binutils 2.24 or later
diff --git a/automation/gitlab-ci/build.yaml b/automation/gitlab-ci/build.yaml
index 6d2cb18b8883..347fe1b5a8db 100644
--- a/automation/gitlab-ci/build.yaml
+++ b/automation/gitlab-ci/build.yaml
@@ -638,21 +638,6 @@ debian-stretch-gcc:
   variables:
     CONTAINER: debian:stretch
 
-debian-stretch-clang:
-  extends: .clang-x86-64-build
-  variables:
-    CONTAINER: debian:stretch
-
-debian-stretch-clang-debug:
-  extends: .clang-x86-64-build-debug
-  variables:
-    CONTAINER: debian:stretch
-
-debian-stretch-32-clang-debug:
-  extends: .clang-x86-32-build-debug
-  variables:
-    CONTAINER: debian:stretch-i386
-
 debian-stretch-32-gcc-debug:
   extends: .gcc-x86-32-build-debug
   variables:
@@ -725,16 +710,6 @@ ubuntu-trusty-gcc-debug:
   variables:
     CONTAINER: ubuntu:trusty
 
-ubuntu-xenial-clang:
-  extends: .clang-x86-64-build
-  variables:
-    CONTAINER: ubuntu:xenial
-
-ubuntu-xenial-clang-debug:
-  extends: .clang-x86-64-build-debug
-  variables:
-    CONTAINER: ubuntu:xenial
-
 ubuntu-xenial-gcc:
   extends: .gcc-x86-64-build
   variables:
@@ -745,16 +720,6 @@ ubuntu-xenial-gcc-debug:
   variables:
     CONTAINER: ubuntu:xenial
 
-ubuntu-bionic-clang:
-  extends: .clang-x86-64-build
-  variables:
-    CONTAINER: ubuntu:bionic
-
-ubuntu-bionic-clang-debug:
-  extends: .clang-x86-64-build-debug
-  variables:
-    CONTAINER: ubuntu:bionic
-
 ubuntu-bionic-gcc:
   extends: .gcc-x86-64-build
   variables:
@@ -775,16 +740,6 @@ ubuntu-focal-gcc-debug:
   variables:
     CONTAINER: ubuntu:focal
 
-ubuntu-focal-clang:
-  extends: .clang-x86-64-build
-  variables:
-    CONTAINER: ubuntu:focal
-
-ubuntu-focal-clang-debug:
-  extends: .clang-x86-64-build-debug
-  variables:
-    CONTAINER: ubuntu:focal
-
 opensuse-leap-clang:
   extends: .clang-x86-64-build
   variables:
-- 
2.44.0