[cmake] fallback cJSON detection

libfreerdp/CMakeLists.txt

@@ -259,9 +259,18 @@ endif()
 if (WITH_AAD)
     if (NOT cJSON_FOUND)
         find_package(PkgConfig REQUIRED)
-        pkg_check_modules(CJSON REQUIRED libcjson)
+        pkg_check_modules(CJSON libcjson)
+    endif()
+    if (NOT CJSON_LIBRARIES OR NOT CJSON_INCLUDE_DIRS)
+        find_path(CJSON_INCLUDE_DIRS
+            NAMES cjson/cJSON.h
+            REQUIRED
+        )
+        find_library(CJSON_LIBRARIES
+            NAMES cjson
+            REQUIRED
+        )
     endif()
-    include_directories(${CJSON_INCLUDE_DIRS})
 
     freerdp_library_add(${CJSON_LIBRARIES})
     include_directories(${CJSON_INCLUDE_DIRS})