Combine lib dependencies into static libktx on all desktop platforms (#1090)

Previously this was only done on macOS - using `libtool`. Changed to
a simple, though hard to find, cross-platform way to do this via CMake.

Add CI test of build and use of a static library.

Remove macOS 13 build from CI as these runner images have been
retired from GitHub Actions.

.github/workflows/check-libktx-only.yml

@@ -59,6 +59,7 @@ jobs:
       matrix:
         os: [ macos-latest, ubuntu-latest, windows-latest ]
         config: [ Release ]
+        static: [ OFF, ON ]
         generator: [ 'Ninja Multi-Config' ]
         exclude:
           - os: windows-latest
@@ -70,6 +71,12 @@ jobs:
           # how to change the behaviour. Use VS.
           - os: windows-latest
             generator: 'Visual Studio 17 2022'
+            config: Release
+            static: OFF
+          - os: windows-latest
+            generator: 'Visual Studio 17 2022'
+            config: Release
+            static: ON
 
     runs-on: ${{ matrix.os }}
     env:
@@ -78,6 +85,8 @@ jobs:
       BUILD_DIR_UKP: "build/ukp"
       SOURCE_DIR_LIB: "lib"
       SOURCE_DIR_UKP: "tests/use-ktx"
+      # In theory it should not matter, but this image is chosen to exercise
+      # some of the functions in one of the library dependencies.
       KTX2_TEST_FILE: "tests/testimages/kodim17_basis.ktx2"
       WERROR: ON
 
@@ -96,10 +105,9 @@ jobs:
     - name: Build libktx with top-level project
       run: cmake --build ${{ env.BUILD_DIR_TL }} --config=Release
 
-    - name: Configure as sub-project
-      run: cmake -S ${{ env.SOURCE_DIR_UKP }} -B ${{ env.BUILD_DIR_UKP }} -G "${{ matrix.generator }}" -DLIBKTX_WERROR=${{ env.WERROR }}
-
-    - name: Build use-ktx and libktx projects
+    - name: Configure as sub-project, static library is ${{ matrix.static }}
+      run: cmake -S ${{ env.SOURCE_DIR_UKP }} -B ${{ env.BUILD_DIR_UKP }} -G "${{ matrix.generator }}" -DLIBKTX_WERROR=${{ env.WERROR }} -DUSE_STATIC_LIBRARY=${{ matrix.static }}
+    - name: Build use-ktx and libktx projects, static library is ${{ matrix.static }}
       run: cmake --build ${{ env.BUILD_DIR_UKP }} --config=Release
 
     - name: Prepare version number and architecture for artifact
@@ -121,6 +129,7 @@ jobs:
       run: ${{ env.BUILD_DIR_UKP }}/Release/use-ktx ${{ env.KTX2_TEST_FILE }}
 
     - name: Upload artifact libktx
+      if: matrix.static == 'OFF'
       uses: actions/upload-artifact@v4
       with:
         name: libktx-${{ env.KTX_VERSION }}-${{ runner.os }}-${{ env.ARCH }}

.github/workflows/macos.yml

@@ -88,16 +88,6 @@ jobs:
                doc: ON, jni: ON, loadtests: OpenGL+Vulkan, py: ON, tools: ON, tools_cts: ON,
                package: YES, sse: ON, opencl: OFF
             }
-          - name: Test macOS 13 build
-            os: macos-13
-            options: {
-              # graphviz no longer supports macOS 13 so doc: OFF.
-              # ts-graphviz/setup-graphviz@v2 does not support specifying a
-              # version on macOS.
-              config: 'Debug,Release', platform: macOS,
-              doc: OFF, jni: ON, loadtests: OpenGL+Vulkan, py: ON, tests: OFF, tools: ON, tools_cts: OFF,
-              package: OFF, sse: ON, opencl: OFF
-            }
           - name: Build for iOS
             os: macos-latest
             generator: Xcode

lib/CMakeLists.txt

@@ -470,19 +470,10 @@ macro(common_libktx_settings target enable_write library_type)
 endmacro(common_libktx_settings)
 
 macro(add_lib_dependencies target lib)
-    if(NOT BUILD_SHARED_LIBS AND APPLE)
+    if(NOT BUILD_SHARED_LIBS)
         # Make a single static library to simplify linking.
-        add_dependencies(${target} ${lib})
-        add_custom_command( TARGET ${target}
-            POST_BUILD
-            COMMAND libtool -static -o $<TARGET_FILE:${target}> $<TARGET_FILE:${target}> $<TARGET_FILE:${lib}>
-        )
+        target_sources(${target} PRIVATE $<TARGET_OBJECTS:${lib}>)
         target_include_directories(${target} PRIVATE $<TARGET_PROPERTY:${lib},INTERFACE_INCLUDE_DIRECTORIES>)
-
-        # Don't know libtool equivalent on Windows or Emscripten. Applications
-        # will have to link with  both ktx and ${ASTCENC_LIB_TARGET}. Static libs
-        # are unlikely to be used on Windows so not a problem there. For Emscripten
-        # everything is built into the JS module so not an issue there either.
     else()
         target_link_libraries(${target} PRIVATE ${lib})
     endif()

tests/use-ktx/CMakeLists.txt

@@ -22,6 +22,8 @@ project(use-ktx
     DESCRIPTION "Test using libktx project independently of KTX-Software"
 )
 
+option(USE_STATIC_LIBRARY "Build and use static library" OFF)
+
 set(path_to_ktx ../../lib)
 
 if(WIN32)
@@ -31,11 +33,18 @@ if(WIN32)
     set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 endif()
 
+if(USE_STATIC_LIBRARY)
+    message("Building and using static library")
+    set(BUILD_SHARED_LIBS OFF)
+else()
+    message("Building and using shared library")
+endif()
 add_subdirectory(${path_to_ktx} ktx)
 
 add_executable(use-ktx
     use-ktx.cc
 )
 
+# libktx adds KHRONOS_STATIC as a public define so no need to set it here.
 target_compile_features(use-ktx PRIVATE cxx_std_20)
 target_link_libraries(use-ktx PRIVATE ktx)