Improve coverage of GH build workflow

This adds Null-only and Wayland-only builds, while rearranging jobs by
host OS instead of by target platform.

Every useful combination of platforms is now being built, except for
Null-only with Win32 time and threading.  This combination does not
compile on VS due to some non-standard array initializers.

.github/workflows/build.yml

@@ -9,8 +9,8 @@ permissions:
     contents: read
 
 jobs:
-    build-linux-x11-clang:
-        name: X11 (Linux, Clang)
+    build-linux-clang:
+        name: Linux (Clang)
         runs-on: ubuntu-latest
         env:
             CC: clang
@@ -20,75 +20,78 @@ jobs:
             - name: Install dependencies
               run: |
                   sudo apt update
-                  sudo apt install libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev libxext-dev
+                  sudo apt install libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev libxext-dev wayland-protocols libwayland-dev libxkbcommon-dev
 
-            - name: Configure static library
-              run: cmake -B build-static
-            - name: Build static library
-              run: cmake --build build-static --parallel
+            - name: Configure Null shared library
+              run: cmake -B build-null-shared -D GLFW_BUILD_WAYLAND=OFF -D GLFW_BUILD_X11=OFF -D BUILD_SHARED_LIBS=ON
+            - name: Build Null shared library
+              run: cmake --build build-null-shared --parallel
 
-            - name: Configure shared library
-              run: cmake -B build-shared -D BUILD_SHARED_LIBS=ON
-            - name: Build shared library
-              run: cmake --build build-shared --parallel
+            - name: Configure X11 shared library
+              run: cmake -B build-x11-shared -D GLFW_BUILD_WAYLAND=OFF -D GLFW_BUILD_X11=ON -D BUILD_SHARED_LIBS=ON
+            - name: Build X11 shared library
+              run: cmake --build build-x11-shared --parallel
 
-    build-linux-full-clang:
-        name: X11+Wayland (Linux, Clang)
-        runs-on: ubuntu-latest
-        env:
-            CC: clang
-            CFLAGS: -Werror
-        steps:
-            - uses: actions/checkout@v3
-            - name: Install dependencies
-              run: |
-                  sudo apt update
-                  sudo apt install libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev libxext-dev wayland-protocols libwayland-dev libxkbcommon-dev
+            - name: Configure Wayland shared library
+              run: cmake -B build-wayland-shared -D GLFW_BUILD_WAYLAND=ON -D GLFW_BUILD_X11=OFF -D BUILD_SHARED_LIBS=ON
+            - name: Build Wayland shared library
+              run: cmake --build build-wayland-shared --parallel
 
-            - name: Configure static library
-              run: cmake -B build-static -D GLFW_BUILD_WAYLAND=ON
-            - name: Build static library
-              run: cmake --build build-static --parallel
+            - name: Configure Wayland+X11 static library
+              run: cmake -B build-full-static -D GLFW_BUILD_WAYLAND=ON -D GLFW_BUILD_X11=ON
+            - name: Build Wayland+X11 static library
+              run: cmake --build build-full-static --parallel
 
-            - name: Configure shared library
-              run: cmake -B build-shared -D GLFW_BUILD_WAYLAND=ON -D BUILD_SHARED_LIBS=ON
-            - name: Build shared library
-              run: cmake --build build-shared --parallel
+            - name: Configure Wayland+X11 shared library
+              run: cmake -B build-full-shared -D GLFW_BUILD_WAYLAND=ON -D BUILD_SHARED_LIBS=ON -D GLFW_BUILD_X11=ON
+            - name: Build Wayland+X11 shared library
+              run: cmake --build build-full-shared --parallel
 
-    build-macos-cocoa-clang:
-        name: Cocoa (macOS, Clang)
+    build-macos-clang:
+        name: macOS (Clang)
         runs-on: macos-latest
         env:
             CFLAGS: -Werror
             MACOSX_DEPLOYMENT_TARGET: 10.8
+            CMAKE_OSX_ARCHITECTURES: x86_64;arm64
         steps:
             - uses: actions/checkout@v3
 
-            - name: Configure static library
-              run: cmake -B build-static
-            - name: Build static library
-              run: cmake --build build-static --parallel
+            - name: Configure Null shared library
+              run: cmake -B build-null-shared -D GLFW_BUILD_COCOA=OFF -D BUILD_SHARED_LIBS=ON
+            - name: Build Null shared library
+              run: cmake --build build-null-shared --parallel
+
+            - name: Configure Cocoa static library
+              run: cmake -B build-cocoa-static
+            - name: Build Cocoa static library
+              run: cmake --build build-cocoa-static --parallel
 
-            - name: Configure shared library
-              run: cmake -B build-shared -D BUILD_SHARED_LIBS=ON
-            - name: Build shared library
-              run: cmake --build build-shared --parallel
+            - name: Configure Cocoa shared library
+              run: cmake -B build-cocoa-shared -D BUILD_SHARED_LIBS=ON
+            - name: Build Cocoa shared library
+              run: cmake --build build-cocoa-shared --parallel
 
-    build-windows-win32-vs2022:
-        name: Win32 (Windows, VS2022)
+    build-windows-vs2022:
+        name: Windows (VS2022)
         runs-on: windows-latest
         env:
             CFLAGS: /WX
         steps:
             - uses: actions/checkout@v3
 
-            - name: Configure static library
-              run: cmake -B build-static -G "Visual Studio 17 2022"
-            - name: Build static library
-              run: cmake --build build-static --parallel
+            - name: Configure Win32 shared x86 library
+              run: cmake -B build-win32-shared-x86 -G "Visual Studio 17 2022" -A Win32 -D BUILD_SHARED_LIBS=ON
+            - name: Build Win32 shared x86 library
+              run: cmake --build build-win32-shared-x86 --parallel
+
+            - name: Configure Win32 static x64 library
+              run: cmake -B build-win32-static-x64 -G "Visual Studio 17 2022" -A x64
+            - name: Build Win32 static x64 library
+              run: cmake --build build-win32-static-x64 --parallel
 
-            - name: Configure shared library
-              run: cmake -B build-shared -G "Visual Studio 17 2022" -D BUILD_SHARED_LIBS=ON
-            - name: Build shared library
-              run: cmake --build build-shared --parallel
+            - name: Configure Win32 shared x64 library
+              run: cmake -B build-win32-shared-x64 -G "Visual Studio 17 2022" -A x64 -D BUILD_SHARED_LIBS=ON
+            - name: Build Win32 shared x64 library
+              run: cmake --build build-win32-shared-x64 --parallel