Bump minimal CMake version to 3.5 to silence a CMake 3.27 warning.

CMakeLists.txt

@@ -23,7 +23,8 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
-cmake_minimum_required(VERSION 3.4)
+# Matches Corrade requirement, see its root CMakeLists for more information.
+cmake_minimum_required(VERSION 3.5)
 
 option(HUNTER_ENABLED "Get dependencies (Corrade, GLFW, SDL2, ...) via Hunter" OFF)
 if(HUNTER_ENABLED)
@@ -503,15 +504,7 @@ if(_MAGNUM_ACCEPT_DEPRECATED_UNPREFIXED_OPTIONS AND MAGNUM_BUILD_DEPRECATED)
     endforeach()
 
     if(_MAGNUM_WARN_DEPRECATED_UNPREFIXED_OPTION)
-        # CMake 3.5+ has deprecation warnings enabled by default (which makes
+        message(DEPRECATION "Unprefixed options such as ${_MAGNUM_WARN_DEPRECATED_UNPREFIXED_OPTION} are deprecated, use MAGNUM_${_MAGNUM_WARN_DEPRECATED_UNPREFIXED_OPTION} instead. Delete the unprefixed variable from CMake cache or set both to the same value to silence this warning.")
-        # sense), 3.4 not. Use a warning there instead.
-        # TODO: drop when 3.4 is not supported anymore
-        if(CMAKE_VERSION VERSION_LESS 3.5)
-            set(DEPRECATION_OR_WARNING WARNING)
-        else()
-            set(DEPRECATION_OR_WARNING DEPRECATION)
-        endif()
-        message(${DEPRECATION_OR_WARNING} "Unprefixed options such as ${_MAGNUM_WARN_DEPRECATED_UNPREFIXED_OPTION} are deprecated, use MAGNUM_${_MAGNUM_WARN_DEPRECATED_UNPREFIXED_OPTION} instead. Delete the unprefixed variable from CMake cache or set both to the same value to silence this warning.")
     endif()
 endif()
 

doc/building.dox

@@ -41,7 +41,7 @@ Minimal set of tools and libraries required for building is:
     everything needed are **GCC** >= 4.8.1, **Clang** >= 6 (or equivalently
     **Apple Clang** >= 10) and **MSVC** >= 2015. On Windows you can also use
     **Clang-CL** or **MinGW-w64**.
--   **CMake** >= 3.4
+-   **CMake** >= 3.5
 -   **Corrade** --- Plugin management and utility library. See
     @ref building-corrade "Corrade download and installation guide" for more
     information.

doc/changelog.dox

@@ -38,6 +38,14 @@ See also:
 
 @section changelog-latest Changes since 2020.06
 
+@subsection changelog-latest-dependencies Dependency changes
+
+-   Minimal supported CMake version is now 3.5, changed from 3.4, since CMake
+    3.27+ warns if a compatibility with CMake below 3.5 is requested. Older
+    versions are not supported anymore and all workarounds for them were
+    removed. This is a conservative change, as there are no known supported
+    distributions which would have anything older than 3.5.
+
 @subsection changelog-latest-new New features
 
 -   MSVC 2022 support. See also [mosra/corrade#124](https://github.com/mosra/corrade/issues/124)

doc/generated/CMakeLists.txt

@@ -23,7 +23,7 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
-cmake_minimum_required(VERSION 3.4)
+cmake_minimum_required(VERSION 3.5)
 
 project(MagnumDocumentationImageGenerator CXX)
 

doc/getting-started.dox

@@ -67,7 +67,7 @@ you actually use are built (and excluding the subdirectory from the `install`
 target as well).
 
 @code{.cmake}
-cmake_minimum_required(VERSION 3.4)
+cmake_minimum_required(VERSION 3.5)
 project(MyApplication)
 
 set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/modules/" ${CMAKE_MODULE_PATH})

package/ci/circleci.yml

@@ -313,7 +313,7 @@ jobs:
         count: 16
     - install-gcc-4_8
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - setup-null-openal-driver
     - build:
         script: unix-desktop.sh
@@ -326,7 +326,7 @@ jobs:
       CONFIGURATION: Debug
       PLATFORM_GL_API: GLX
     steps:
-    # Not installing the old GCC 4.8 and CMake 3.4 to speed up. These are
+    # Not installing the old GCC 4.8 and CMake 3.5 to speed up. These are
     # tested more than enough on other jobs.
     - install-base-linux-arm64:
         extra: libgl1-mesa-dev libsdl2-dev libglfw3-dev libopenal-dev libvulkan-dev
@@ -375,7 +375,7 @@ jobs:
         count: 16
     - install-gcc-4_8
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - install-swiftshader-gles:
         build: ubuntu-16.04
     - build:
@@ -401,7 +401,7 @@ jobs:
         count: 16
     - install-gcc-4_8
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - install-swiftshader-gles:
         build: ubuntu-16.04
     - build:
@@ -434,7 +434,7 @@ jobs:
         count: 16
     - install-gcc-4_8
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - setup-null-openal-driver
     - build:
         script: unix-desktop.sh
@@ -459,7 +459,7 @@ jobs:
         count: 16
     - install-gcc-4_8
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - setup-null-openal-driver
     - build:
         script: unix-desktop.sh
@@ -479,7 +479,7 @@ jobs:
         extra: libgl1-mesa-dev libopenal-dev libvulkan-dev
     - install-clang
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - setup-null-openal-driver
     - build:
         script: unix-desktop.sh
@@ -499,7 +499,7 @@ jobs:
         extra: libgl1-mesa-dev libopenal-dev libvulkan-dev
     - install-clang
     - install-cmake:
-        version: "3.4.3"
+        version: "3.5.2"
     - setup-null-openal-driver
     - build:
         script: unix-desktop.sh