ci: Add scripts to install PVS-Studio in Linux jobs

.gitlab/.gitignore

@@ -20,6 +20,7 @@
 /open-watcom*
 /orangec
 /pellesc
+/pvs-studio
 /python*
 /qt*
 /sccache*

.gitlab/ci/pvs-studio-env.sh

@@ -0,0 +1,13 @@
+.gitlab/ci/pvs-studio.sh
+export PATH=$PWD/.gitlab/pvs-studio/bin:$PATH
+pvs-studio --version
+
+if test -f "$CMAKE_CI_PVS_STUDIO_LICENSE_USER" -a -f "$CMAKE_CI_PVS_STUDIO_LICENSE_KEY"; then
+  pvs-studio-analyzer credentials "$(<"$CMAKE_CI_PVS_STUDIO_LICENSE_USER")" "$(<"$CMAKE_CI_PVS_STUDIO_LICENSE_KEY")"
+else
+ echo "The CMAKE_CI_PVS_STUDIO_LICENSE_USER and CMAKE_CI_PVS_STUDIO_LICENSE_KEY files were not both provided!"
+ exit 1
+fi
+rm -f "$CMAKE_CI_PVS_STUDIO_LICENSE_USER" "$CMAKE_CI_PVS_STUDIO_LICENSE_KEY"
+unset CMAKE_CI_PVS_STUDIO_LICENSE_KEY
+unset CMAKE_CI_PVS_STUDIO_LICENSE_USER

.gitlab/ci/pvs-studio.sh

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+set -e
+
+readonly version="7.42.105112.761"
+
+case "$(uname -s)-$(uname -m)" in
+    Linux-x86_64)
+        # https://files.pvs-studio.com/pvs-studio-7.42.105112.761-x86_64.tgz
+        shatool="sha256sum"
+        sha256sum="0ced11d17855cc172a860f8cc19a89f10adb6ab7185992fb57474118e9bdabd7"
+        filename="pvs-studio-$version-x86_64"
+        ;;
+    *)
+        echo "Unrecognized platform $(uname -s)-$(uname -m)"
+        exit 1
+        ;;
+esac
+readonly shatool
+readonly sha256sum
+
+cd .gitlab
+
+# This URL is only visible inside of Kitware's network.  See above filename table.
+baseurl="https://cmake.org/files/dependencies/internal"
+
+tarball="$filename.tgz"
+echo "$sha256sum  $tarball" > pvs-studio.sha256sum
+curl -OL "$baseurl/$tarball"
+$shatool --check pvs-studio.sha256sum
+tar xzf "$tarball"
+rm "$tarball" pvs-studio.sha256sum
+mv "$filename" "pvs-studio"