Add gcc problem matcher

README.md

@@ -73,7 +73,12 @@ A screenshot and an example (further down) is worth a thousand words:
 
 ### Supported linters
 
-* [flake8](problem-matchers/flake8.json)
-* [mypy](problem-matchers/mypy.json)
+* [flake8](https://flake8.pycqa.org/)
+* [gcc](https://gcc.gnu.org/)
+* [mypy](http://mypy-lang.org/)
+* [shellcheck](https://github.com/koalaman/shellcheck#readme) (`-f gcc` + gcc problem matcher)
+
+For details, sources and licenses of individual problem matchers, see
+[problem-matchers/](problem-matchers/).
 
 Pull Requests with additional linters welcome!

problem-matchers/README.md

@@ -3,5 +3,12 @@
 [Problem Matcher]: https://github.com/actions/toolkit/blob/master/docs/problem-matchers.md
 [GitHub Action: Problem Matcher wrapper]: ..
 
-* flake8: [Copyright © 2019, Patric "TrueBrain" Stout](https://github.com/TrueBrain/actions-flake8/blob/master/LICENSE)
+* flake8:
+  [source](https://github.com/TrueBrain/actions-flake8/blob/7e33a2bcf3bee056945183e6d08d70000de48114/flake8-matcher.json),
+  [Copyright © 2019, Patric "TrueBrain" Stout](https://github.com/TrueBrain/actions-flake8/blob/7e33a2bcf3bee056945183e6d08d70000de48114/LICENSE)
+* gcc:
+  [source](https://github.com/microsoft/vscode-cpptools/blob/a8285cbc0efb5b09c2d2229b0e0772dcb3b602df/Extension/package.json),
+  [Copyright © Microsoft Corporation](https://github.com/microsoft/vscode-cpptools/blob/a8285cbc0efb5b09c2d2229b0e0772dcb3b602df/LICENSE.txt)
 * mypy: [Copyright © 2020 Tomáš Janoušek](../LICENSE)
+
+Pull Requests with additional linters welcome!

problem-matchers/gcc.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "gcc",
+      "pattern": [
+        {
+          "regexp": "^(.*):(\\d+):(\\d+):\\s+(?:fatal\\s+)?(warning|error):\\s+(.*)$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "severity": 4,
+          "message": 5
+        }
+      ]
+    }
+  ]
+}