[Ubuntu 20.04][Cmake] SDL2::SDL2 target was not found

**Describe the bug**

I'm trying to build OpenXray on Ubuntu 20.04. While SDL2 library is installed on my machine:



```

$ sudo apt-get install libsdl2-dev

Reading package lists... Done

Building dependency tree       

Reading state information... Done

libsdl2-dev is already the newest version (2.0.10+dfsg1-3).

0 upgraded, 0 newly installed, 0 to remove and 58 not upgraded.

```

Cmake fails with:

```

  Target "xrCore" links to:



    SDL2::SDL2



  but the target was not found.  Possible reasons include:



    * There is a typo in the target name.

    * A find_package call is missing for an IMPORTED target.

    * An ALIAS target is missing.

```



**Desktop (please complete the following information):**

 - OS: Ubuntu 20.04.6 LTS

 - Cmake 3.28.1

 - OpenXRay `dev` branch



**Additional context**

- May be related to #1535 

- Build from branch `2188-november-2023-rc1` works fine



**Full Cmake logs**

```

$ cmake ..

-- CMAKE_VERSION: 3.28.1

-- The C compiler identification is GNU 9.4.0

-- The CXX compiler identification is GNU 9.4.0

-- Detecting C compiler ABI info

-- Detecting C compiler ABI info - done

-- Check for working C compiler: /usr/bin/cc - skipped

-- Detecting C compile features

-- Detecting C compile features - done

-- Detecting CXX compiler ABI info

-- Detecting CXX compiler ABI info - done

-- Check for working CXX compiler: /usr/bin/c++ - skipped

-- Detecting CXX compile features

-- Detecting CXX compile features - done

-- CMAKE_VERBOSE_MAKEFILE: FALSE

-- git commit: be53de4e2217b7e52be76d7d371e9d34791a1789

-- git branch: dev

-- CMAKE_SYSTEM_PROCESSOR: x86_64

-- CMAKE_BUILD_TYPE: Release

-- MASTER_GOLD: ON

-- STATIC_BUILD: ON

-- CMAKE_UNITY_BUILD: OFF

-- USE_ADDRESS_SANITIZER: OFF

-- USE_LTO: ON

-- Performing Test GOLD_LINKER_AVAILABLE

-- Performing Test GOLD_LINKER_AVAILABLE - Success

-- Performing Test LLD_LINKER_AVAILABLE

-- Performing Test LLD_LINKER_AVAILABLE - Success

-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so   

-- Found GLEW: /usr/include (found version "2.1.0") 

-- Found OpenAL: /usr/lib/x86_64-linux-gnu/libopenal.so  

-- Found JPEG: /usr/lib/x86_64-linux-gnu/libjpeg.so (found version "80") 

-- Found Ogg: /usr/lib/x86_64-linux-gnu/libogg.so  

-- Found Vorbis: /usr/lib/x86_64-linux-gnu/libvorbis.so   

-- Found Theora: /usr/lib/x86_64-linux-gnu/libtheora.so   

-- Found LZO: /usr/lib/x86_64-linux-gnu/liblzo2.so  

-- Could NOT find mimalloc (missing: mimalloc_DIR)

Using standard memory allocator

-- The ASM compiler identification is GNU

-- Found assembler: /usr/bin/cc

rm -f luajit libluajit.a libluajit.so host/minilua host/buildvm lj_vm.S lj_bcdef.h lj_ffdef.h lj_libdef.h lj_recdef.h lj_folddef.h host/buildvm_arch.h jit/vmdef.lua *.o host/*.o *.obj *.lib *.exp *.dll *.exe *.manifest *.pdb *.ilk

-- Configuring done (1.6s)

CMake Error at src/xrCore/CMakeLists.txt:444 (target_link_libraries):

  Target "xrCore" links to:



    SDL2::SDL2



  but the target was not found.  Possible reasons include:



    * There is a typo in the target name.

    * A find_package call is missing for an IMPORTED target.

    * An ALIAS target is missing.







-- Generating done (0.4s)

CMake Generate step failed.  Build files cannot be regenerated correctly.

```

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