Fix clang-tidy on CI and introduce .clang-tidy file

.clang-tidy

@@ -0,0 +1,8 @@
+---
+Checks: "-*,
+         boost-*,
+         portability-*,
+"
+WarningsAsErrors: ''
+HeaderFilterRegex: ''
+FormatStyle: none

.gitlab-ci.yml

@@ -55,26 +55,6 @@ variables:
     paths:
       - build/install/
 
-Clang_Tidy:
-  extends: .Ubuntu_Image
-  stage: build
-  rules:
-    - if: '$CI_PIPELINE_SOURCE == "schedule"'
-  before_script:
-    - CI/install_debian_deps.sh gcc openmw-deps openmw-deps-dynamic clang-tidy clang
-  script:
-    - CI/before_script.linux.sh
-    - cd build
-    - cmake --build . -- -j $(nproc) openmw esmtool bsatool niftest openmw-wizard openmw-launcher openmw-iniimporter openmw-essimporter
-  variables:
-    CC: clang
-    CXX: clang++
-    CI_CLANG_TIDY: 1
-  timeout: 8h
-  artifacts:
-    paths: []
-    expire_in: 1 minute
-
 Coverity:
   extends: .Ubuntu_Image
   stage: build
@@ -261,12 +241,13 @@ Ubuntu_GCC:
 Ubuntu_Clang:
   extends: .Ubuntu
   before_script:
-    - CI/install_debian_deps.sh clang openmw-deps openmw-deps-dynamic
+    - CI/install_debian_deps.sh clang clang-tidy openmw-deps openmw-deps-dynamic
   cache:
     key: Ubuntu_Clang.v2
   variables:
     CC: clang
     CXX: clang++
+    CI_CLANG_TIDY: 1
     CCACHE_SIZE: 2G
   # When CCache doesn't exist (e.g. first build on a fork), build takes more than 1h, which is the default for forks.
   timeout: 2h

CI/before_script.linux.sh

@@ -43,7 +43,7 @@ fi
 
 if [[ $CI_CLANG_TIDY ]]; then
 	CMAKE_CONF_OPTS+=(
-	      -DCMAKE_CXX_CLANG_TIDY="clang-tidy;-checks=-*,boost-*,clang-analyzer-*,concurrency-*,performance-*,-header-filter=.*,bugprone-*,misc-definitions-in-headers,misc-misplaced-const,misc-redundant-expression,-bugprone-narrowing-conversions"
+	      -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--warnings-as-errors=*"
 	)
 fi