Add AddressSanitizer

Do not override the compilers (the CC and CXX environment variables).
For some reason, using CC=clang and CXX=clang++ (Clang 14.0.0) with
AddressSanitixer results in segmentation faults in the ubuntu-latest os
image.

.github/workflows/ci-unix-static-sanitized.yml

@@ -11,11 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        sanitizer: [ undefined ] # TODO(yguyon): Add address, memory, thread
-
-    env:
-      CC: clang
-      CXX: clang++
+        sanitizer: [ address, undefined ] # TODO(yguyon): Add memory, thread
 
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
@@ -28,35 +24,39 @@ jobs:
       - uses: ilammy/setup-nasm@13cbeb366c45c4379d3478cdcbadd8295feb5028 # v1.5.1
         with:
           version: 2.15.05
+        env:
+          CC: clang
+          CXX: clang++
       - uses: seanmiddleditch/gha-setup-ninja@8b297075da4cd2a5f1fd21fe011b499edf06e9d2 # v4
       - run: pip install meson
 
-      - name: Cache external dependencies
-        id: cache-ext
-        uses: actions/cache@ab5e6d0c87105b4c9c2047343972218f562e4319 # v4.0.1
-        with:
-          path: ext
-          key: ${{ runner.os }}-${{ matrix.sanitizer }}-${{ hashFiles('ext/*.cmd') }}
-
       - name: Build aom
         if: steps.cache-ext.outputs.cache-hit != 'true'
         working-directory: ./ext
         run: >
           sed -i -e 's/cmake -G Ninja \(.*\) \.\./cmake -G Ninja \1 -DSANITIZE=${{ matrix.sanitizer }} ../g' aom.cmd
 
           ./aom.cmd
+        env:
+          CC: clang
+          CXX: clang++
       - name: Build dav1d
         if: steps.cache-ext.outputs.cache-hit != 'true'
         working-directory: ./ext
         run: >
           sed -i -e 's/meson setup \(.*\) \.\./meson setup \1 '"-Db_sanitize=${{ matrix.sanitizer }} -Db_lundef=false"' ../g' dav1d.cmd
 
           ./dav1d.cmd
+        env:
+          CC: clang
+          CXX: clang++
       - name: Build libyuv
         if: steps.cache-ext.outputs.cache-hit != 'true'
         working-directory: ./ext
         run: ./libyuv.cmd
         env:
+          CC: clang
+          CXX: clang++
           CFLAGS: -fsanitize=${{ matrix.sanitizer }}
           CXXFLAGS: -fsanitize=${{ matrix.sanitizer }}
           LDFLAGS: -fsanitize=${{ matrix.sanitizer }}
@@ -65,6 +65,8 @@ jobs:
         working-directory: ./ext
         run: ./libsharpyuv.cmd
         env:
+          CC: clang
+          CXX: clang++
           CFLAGS: -fsanitize=${{ matrix.sanitizer }}
           CXXFLAGS: -fsanitize=${{ matrix.sanitizer }}
           LDFLAGS: -fsanitize=${{ matrix.sanitizer }}
@@ -73,6 +75,9 @@ jobs:
         working-directory: ./ext
         # Note: "apt install googletest" is sometimes insufficient for find_package(GTest) so build in ext/ instead.
         run: bash -e googletest.cmd
+        env:
+          CC: clang
+          CXX: clang++
 
       - name: Prepare libavif (cmake)
         run: >
@@ -83,6 +88,8 @@ jobs:
           -DAVIF_BUILD_EXAMPLES=ON -DAVIF_BUILD_APPS=ON
           -DAVIF_BUILD_TESTS=ON -DAVIF_ENABLE_GTEST=ON -DAVIF_LOCAL_GTEST=ON
         env:
+          CC: clang
+          CXX: clang++
           CFLAGS: -fsanitize=${{ matrix.sanitizer }}
           CXXFLAGS: -fsanitize=${{ matrix.sanitizer }}
           LDFLAGS: -fsanitize=${{ matrix.sanitizer }}
@@ -91,5 +98,6 @@ jobs:
         run: ninja
       - name: Run AVIF Tests
         working-directory: ./build
-        # ASAN_OPTIONS=allocator_may_return_null=1 may be necessary for address sanitizer.
         run: ctest -j $(getconf _NPROCESSORS_ONLN) --output-on-failure
+        env:
+          ASAN_OPTIONS: allocator_may_return_null=1