From 88f4f090a80ea6129f83c3ce855537a97cd6057a Mon Sep 17 00:00:00 2001
From: timomrs <92291334+timomrs@users.noreply.github.com>
Date: Sat, 8 Jan 2022 06:33:35 +0200
Subject: [PATCH] Allow using json_cpp in other sublibraries (#1145)

If another sublibrary also imports jsoncpp, `FindJsonCpp.cmake` fails with error message `add_library cannot create imported target Jsoncpp_lib because another target with the same name already exists.`.  Adding the `if (NOT TARGET Jsoncpp_lib)`-guard fixes this.

It might be useful to check if there's a similar problem with other sublibraries included by Drogon.
---
 cmake_modules/FindJsoncpp.cmake | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cmake_modules/FindJsoncpp.cmake b/cmake_modules/FindJsoncpp.cmake
index 6c10eb28..d220e70c 100755
--- a/cmake_modules/FindJsoncpp.cmake
+++ b/cmake_modules/FindJsoncpp.cmake
@@ -58,7 +58,9 @@ if(Jsoncpp_FOUND)
         )
     endif(jsoncpp_ver LESS 1.7)
   endif()
-  add_library(Jsoncpp_lib INTERFACE IMPORTED)
+  if (NOT TARGET Jsoncpp_lib)
+          add_library(Jsoncpp_lib INTERFACE IMPORTED)
+  endif()
   set_target_properties(Jsoncpp_lib
                         PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
                                    "${JSONCPP_INCLUDE_DIRS}"