[CMake] Removed option OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT.

scripts/cmake/SubmoduleSetup.cmake

@@ -3,16 +3,10 @@ if(NOT IS_GIT_REPO)
 endif()
 
 # This file initializes the required submodules
-set(OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT "" CACHE STRING
-    "User given submodules which should be checked out by CMake.")
-if(NOT OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT)
-    set(OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT "")
-endif()
 set(REQUIRED_SUBMODULES
     ThirdParty/cmake-modules
     ThirdParty/iphreeqc/src
     ThirdParty/json-cmake
-    ${OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT}
 )
 if(OGS_USE_XDMF)
     list(APPEND REQUIRED_SUBMODULES ThirdParty/xdmf)

web/content/docs/devguide/advanced/configuration-options.md

@@ -43,7 +43,6 @@ CMake switches to enable / disable parts of OGS.
 ### Advanced options
 
 - `OGS_CXX_FLAGS` - Appends user-given compiler flags. Note that existing (CMake-given) flags are not replaced.
-- `OGS_ADDITIONAL_SUBMODULES_TO_CHECKOUT` - Specifies optional submodules which are checked out at CMake-time.
 - `OGS_PACKAGE_ADDITIONAL_BINARIES` - Package additional binaries (given as a `;`-separated list with relative paths to `CMAKE_BINARY_DIR`) into redistributables. Is used for bundling the OGS File Converter with the Data Explorer.
 - `OGS_USE_OPTIONAL_SUBMODULES` - Includes optional submodules into the build. The submodules have to be checked out before. Defaults to ON.
 - `OGS_CPU_ARCHITECTURE` - Optimizes for the given CPU architecture see [-march](https://gcc.gnu.org/onlinedocs/gcc-4.5.3/gcc/i386-and-x86_002d64-Options.html)-flag. Defaults to `native`. For redistributable binaries set to `generic` on Linux and `core2` on Mac OS.