Simplyfy nlohmann_json integration

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "subprojects/nlohmann_json"]
-	path = subprojects/nlohmann_json
-	url = https://github.com/nlohmann/json.git

CMakeLists.txt

@@ -7,7 +7,8 @@ set(CMAKE_MODULE_PATH "${CMAKE_HOME_DIRECTORY}/cmake")
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-#include(InstallRequiredSystemLibraries)
+# For SingleApplication and nlohmann_json
+include(FetchContent)
 
 if(MSVC)
   add_compile_options(/W4 /WX)
@@ -29,7 +30,6 @@ if(KIMA2_USE_EXTERNAL_JSON)
   find_package(nlohmann_json REQUIRED)
 endif()
 
-add_subdirectory(subprojects)
 add_subdirectory(src)
 
 #if(NOT CMAKE_BUILD_TYPE OR CMAKE_BUILD_TYPE MATCHES Debug)

src/core/CMakeLists.txt

@@ -3,9 +3,8 @@ set(Boost_USE_STATIC_LIBS ON)
 find_package(Boost 1.78 REQUIRED)
 find_package(SQLite3 REQUIRED)
 
-# Because csv-parser needs threads:
-
-find_package(fmt)
+FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz)
+FetchContent_MakeAvailable(json)
 
 set(CORE_SOURCES
     database.cpp
@@ -23,7 +22,7 @@ set(CORE_SOURCES
 
 
 add_library(core STATIC ${CORE_SOURCES})
-#target_include_directories(core PRIVATE ${PROJECT_SOURCE_DIR}/subprojects/csv-parser/single_include)
+
 if (WIN32)
     target_link_libraries(core PRIVATE sqlite3 nlohmann_json::nlohmann_json)
     target_link_libraries(core PRIVATE bcrypt)

src/gui/CMakeLists.txt

@@ -11,7 +11,6 @@ set(CMAKE_AUTORCC ON)
 find_package(Qt6 COMPONENTS Widgets Network PrintSupport CONFIG REQUIRED)
 
 # For SingleApplication:
-include(FetchContent)
 set(QT_DEFAULT_MAJOR_VERSION 6 CACHE STRING "Qt version to use, defaults to 6")
 set(QAPPLICATION_CLASS QApplication CACHE STRING "Inheritance class for SingleApplication")
 FetchContent_Declare(

subprojects/CMakeLists.txt

@@ -1,5 +0,0 @@
-if(NOT KIMA2_USE_EXTERNAL_JSON)
-  set(JSON_BuildTests OFF CACHE INTERNAL "")
-  add_subdirectory(nlohmann_json EXCLUDE_FROM_ALL)
-endif()
-#add_subdirectory(csv-parser)

subprojects/nlohmann_json

@@ -1 +0,0 @@
-Subproject commit 9cca280a4d0ccf0c08f47a99aa71d1b0e52f8d03