add support for fetching

CI/before_script.linux.sh

@@ -40,6 +40,7 @@ if [[ $CI_OPENMW_USE_STATIC_DEPS ]]; then
         -DOPENMW_USE_SYSTEM_OSG=OFF
         -DOPENMW_USE_SYSTEM_BULLET=OFF
         -DOPENMW_USE_SYSTEM_SQLITE3=OFF
+        -DOPENMW_USE_SYSTEM_CXXOPTS=OFF
         -DOPENMW_USE_SYSTEM_RECASTNAVIGATION=OFF
     )
 fi

CMakeLists.txt

@@ -236,9 +236,6 @@ find_package(OpenGL REQUIRED)
 
 find_package(LZ4 REQUIRED)
 
-find_package(CXXOPTS REQUIRED)
-include_directories(SYSTEM ${CXXOPTS_INCLUDE_DIRS})
-
 if (USE_QT)
     find_package(QT REQUIRED COMPONENTS Core NAMES Qt6 Qt5)
     if (QT_VERSION_MAJOR VERSION_EQUAL 5)
@@ -366,6 +363,13 @@ if (USE_SYSTEM_TINYXML)
     include_directories(SYSTEM ${TinyXML_INCLUDE_DIRS})
 endif()
 
+# CXXOPTS
+option(OPENMW_USE_SYSTEM_CXXOPTS "Use system provided CXXOPTS library" ON)
+if(OPENMW_USE_SYSTEM_CXXOPTS)
+    find_package(CXXOPTS REQUIRED)
+endif()
+include_directories(SYSTEM ${CXXOPTS_INCLUDE_DIRS})
+
 # Platform specific
 if (WIN32)
     if(NOT MINGW)

extern/CMakeLists.txt

@@ -190,6 +190,17 @@ if(NOT OPENMW_USE_SYSTEM_RECASTNAVIGATION)
     FetchContent_MakeAvailableExcludeFromAll(recastnavigation)
 endif()
 
+if(NOT OPENMW_USE_SYSTEM_CXXOPTS)
+    include(FetchContent)
+    FetchContent_Declare(cxxopts
+            URL https://github.com/jarro2783/cxxopts/archive/refs/tags/v3.1.1.zip
+            URL_HASH SHA512=df8a322f2ecef9bc0e2b17904b008e19e8f6d0384ba2ec95375c15be14953b008550cb119828f03a4eee12795c8df9a558a6eeb8c0e41ad7092b90270d517f5f
+            SOURCE_DIR fetched/cxxopts
+            )
+    FetchContent_MakeAvailableExcludeFromAll(cxxopts)
+    set(CXXOPTS_INCLUDE_DIRS "${cxxopts_SOURCE_DIR}/include" PARENT_SCOPE)
+endif()
+
 if (NOT OPENMW_USE_SYSTEM_SQLITE3)
     include(FetchContent)
     FetchContent_Declare(sqlite3