Add clang-analyzer action

.github/workflows/analyzer.yml

@@ -0,0 +1,25 @@
+on: [push, pull_request]
+# https://github.com/actions/virtual-environments
+# - Ubuntu 20.04 	ubuntu-20.04 	ubuntu-20.04
+# - Ubuntu 18.04 	ubuntu-latest or ubuntu-18.04
+# https://apt.llvm.org/
+# - Bionic (18.04)
+# - Focal (20.04)
+jobs:
+  analyzer:
+    runs-on: ubuntu-18.04
+    name: Analyze with Clang
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install Clang
+      run: |
+        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key 2>/dev/null | sudo apt-key add -
+        sudo add-apt-repository 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-11 main' -y
+        sudo apt-get update -q
+        sudo apt-get install -y clang-11 lld-11 libc++-11-dev libc++abi-11-dev clang-tools-11
+    - name: Clang Analyzer
+      # excludes include/mongoose.h src/mongoose.c
+      # exit code 1 if there is output
+      run: |
+        clang -Iinclude --analyze -Xanalyzer -analyzer-output=text -Xanalyzer -analyzer-disable-checker=deadcode.DeadStores include/[a-ln-z]*.h src/[a-ln-z]*.c src/devices/*.c 2>&1 | tee analyzer.out
+        [ ! -s analyzer.out ]