add CMake option to use system spdlog

BUILD.txt

@@ -33,6 +33,7 @@ Doxygen's cmake configuration provides a number of options:
 - build_search    Build external search tools (doxysearch and doxyindexer).
 - build_doc       Build user manual.
 - use_libclang    Add support for libclang parsing.
+- use_sys_spdlog  Use system spdlog instead of bundled.
 - win_static      Link with /MT in stead of /MD on windows.
 - force_qt=<vers> Forces doxywizard to build using the specified major version, this can be Qt5 or Qt6
 

CMakeLists.txt

@@ -25,6 +25,7 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     option(use_libc++  "Use libc++ as C++ standard library." ON)
 endif()
 option(use_libclang    "Add support for libclang parsing." OFF)
+option(use_sys_spdlog  "Use system spdlog instead of bundled." OFF)
 option(static_libclang "Link to a statically compiled version of LLVM/libclang." OFF)
 option(win_static      "Link with /MT in stead of /MD on windows" OFF)
 option(enable_console  "Enable that executables on Windows get the CONSOLE bit set for the doxywizard executable [development]"  OFF)
@@ -63,6 +64,9 @@ if (use_libclang)
         find_package(LLVM CONFIG REQUIRED)
         find_package(Clang CONFIG REQUIRED)
 endif()
+if (use_sys_spdlog)
+        find_package(spdlog CONFIG REQUIRED)
+endif()
 if (build_wizard)
     if (force_qt STREQUAL "Qt6")
         if (CMAKE_SYSTEM MATCHES "Darwin")

deps/CMakeLists.txt

@@ -1,5 +1,7 @@
 add_subdirectory(libmd5)
 add_subdirectory(liblodepng)
 add_subdirectory(libmscgen)
-add_subdirectory(spdlog)
+if (NOT use_sys_spdlog)
+	add_subdirectory(spdlog)
+endif()
 add_subdirectory(sqlite3)

src/CMakeLists.txt

@@ -11,11 +11,14 @@ include_directories(
     ${PROJECT_SOURCE_DIR}/libxml
     ${PROJECT_SOURCE_DIR}/vhdlparser
     ${PROJECT_SOURCE_DIR}/src
-    ${PROJECT_SOURCE_DIR}/deps/spdlog/include
     ${CLANG_INCLUDEDIR}
     ${GENERATED_SRC}
 )
 
+if (NOT use_sys_spdlog)
+    include_directories(${PROJECT_SOURCE_DIR}/deps/spdlog/include)
+endif()
+
 
 file(MAKE_DIRECTORY ${GENERATED_SRC})
 if (${CMAKE_VERSION} VERSION_EQUAL "3.11.0" OR ${CMAKE_VERSION} VERSION_GREATER "3.11.0")
@@ -389,7 +392,7 @@ target_link_libraries(doxygen PRIVATE
     xml
     doxygen_version
     vhdlparser
-    spdlog
+    spdlog::spdlog
     ${ICONV_LIBRARIES}
     ${CMAKE_THREAD_LIBS_INIT}
     ${EXTRA_LIBS}