cmake - support zstd config packages on non-Windows

Author: Andrej730

CMakeLists.txt

@@ -187,10 +187,17 @@ else()
   endif()
 
   if(WITH_ZSTD)
-    find_package(zstd REQUIRED)
+    find_package(zstd CONFIG)
+    if(zstd_DIR)
+      # Extract include dirs, because some targets (testutillib) use zstd headers without linking to zstd.
+      get_target_property(ZSTD_INCLUDE_DIRS zstd::libzstd INTERFACE_INCLUDE_DIRECTORIES)
+      list(APPEND THIRDPARTY_LIBS zstd::libzstd)
+    else()
+      find_package(zstd REQUIRED)
+      list(APPEND THIRDPARTY_LIBS zstd::zstd)
+    endif()
     add_definitions(-DZSTD)
     include_directories(${ZSTD_INCLUDE_DIRS})
-    list(APPEND THIRDPARTY_LIBS zstd::zstd)
   endif()
 endif()