cmake: find sol2 on system, or use fetch content

Author: mfisher31

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "deps/sol2"]
-	path = deps/sol2
-	url = https://github.com/ThePhD/sol2.git
 [submodule "deps/clap-juce-extensions"]
 	path = deps/clap-juce-extensions
 	url = https://github.com/free-audio/clap-juce-extensions

CMakeLists.txt

@@ -11,8 +11,7 @@ if(APPLE AND ELEMENT_ENABLE_UPDATER)
     include(cmake/FindSparkle.cmake)
 endif()
 include(cmake/FindJack.cmake)
-
-add_subdirectory(deps/sol2 EXCLUDE_FROM_ALL)
+include(cmake/FindSol2.cmake)
 include(cmake/FindJUCE.cmake)
 
 # Global JUCE properties

cmake/FindSol2.cmake

@@ -0,0 +1,8 @@
+find_package(sol2 4.0.0 CONFIG)
+if(NOT sol2_FOUND)
+    FetchContent_Declare(sol2
+        GIT_REPOSITORY https://github.com/ThePhD/sol2.git
+        GIT_TAG c1f95a773c6f8f4fde8ca3efe872e7286afe4444
+        GIT_SHALLOW ON)
+    FetchContent_MakeAvailable(sol2)
+endif()