.e remove unsupported gcc versions 11 and 15

Author: Laguna1989

.github/workflows/build_environments.md

@@ -0,0 +1,47 @@
+# Build Environments Matrix
+
+This page summarizes all environments used in our GitHub Actions workflow for CI builds, grouped by platform.
+
+---
+
+## Linux
+
+| Job Name                        | OS Version | C++ Compiler   | Generator / Options                        |
+|---------------------------------|------------|---------------|--------------------------------------------|
+| clang14                         | 22.04      | clang++-14    | Unix Makefiles, libc++, C++20              |
+| clang15                         | 22.04      | clang++-15    | Unix Makefiles                            |
+| gcc9                            | 22.04      | g++-9         | Unix Makefiles                            |
+| gcc10                           | 22.04      | g++-10        | Unix Makefiles                            |
+| gcc13                           | 24.04      | g++-13        | Unix Makefiles                            |
+| gcc10 unity                     | 22.04      | g++-10        | Unix Makefiles, CMAKE_UNITY_BUILD=yes      |
+| gcc10 ninja in-source           | 22.04      | g++-10        | Ninja                                     |
+| gcc10 ninja out-of-source       | 22.04      | g++-10        | Ninja                                     |
+| gcc10 ninja-unity               | 22.04      | g++-10        | Ninja, CMAKE_UNITY_BUILD=yes               |
+
+---
+
+## macOS
+
+| Job Name                        | OS Version | C++ Compiler   | Generator / Options                        |
+|---------------------------------|------------|---------------|--------------------------------------------|
+| xcode-15.4                      | latest     | AppleClang    | Unix Makefiles                            |
+| xcode-15.4-ninja in-source      | latest     | AppleClang    | Ninja                                     |
+| xcode-15.4-ninja out-of-source  | latest     | AppleClang    | Ninja                                     |
+
+---
+
+## Windows
+
+| Job Name                        | OS Version | C++ Compiler   | Generator / Options                        |
+|---------------------------------|------------|---------------|--------------------------------------------|
+| VS-2019                         | 2019       | MSVC          | Visual Studio 16 2019                     |
+| VS-2019 (clangcl)               | 2019       | clang-cl      | Visual Studio 16 2019 -T clangcl           |
+| VS-latest                       | latest     | MSVC          | Visual Studio 17 2022                     |
+| VS-latest (clangcl)             | latest     | clang-cl      | Visual Studio 17 2022 -T clangcl           |
+
+---
+
+**Notes:**
+- macOS jobs use the AppleClang compiler provided by Xcode.
+- Windows jobs use MSVC or clang-cl via Visual Studio generators.
+- Some jobs use extra CMake flags or different generators to test various build configurations.

.github/workflows/github_actions_build.yml

@@ -74,13 +74,6 @@ jobs:
             generator: '"Unix Makefiles"'
             relative_build_dir_path: ''
 
-          - job-name: 'gcc11'
-            os-version: '24.04'
-            c-compiler: 'gcc-11'
-            cxx-compiler: 'g++-11'
-            generator: '"Unix Makefiles"'
-            relative_build_dir_path: ''
-
           - job-name: 'gcc12'
             os-version: '24.04'
             c-compiler: 'gcc-12'
@@ -102,13 +95,6 @@ jobs:
             generator: '"Unix Makefiles"'
             relative_build_dir_path: ''
 
-          - job-name: 'gcc15'
-            os-version: '24.04'
-            c-compiler: 'gcc-15'
-            cxx-compiler: 'g++-15'
-            generator: '"Unix Makefiles"'
-            relative_build_dir_path: ''
-
           - job-name: 'gcc13 unity'
             os-version: '24.04'
             c-compiler: 'gcc-13'