hunter: download zstd and link against CMake targets

Coauthored by: Reinhold Gschweicher <pyro4hell@gmail.com>

Author: hjmallon

CMakeLists.txt

@@ -620,11 +620,27 @@ endif()
 option(CURL_ZSTD "Set to ON to enable building curl with zstd support." OFF)
 set(HAVE_ZSTD OFF)
 if(CURL_ZSTD)
-  find_package(Zstd REQUIRED)
+  hunter_add_package(zstd)
+  if(HUNTER_ENABLED)
+    find_package(zstd CONFIG REQUIRED)
+    set(Zstd_FOUND "${zstd_FOUND}")
+    set(Zstd_VERSION "${zstd_VERSION}")
+  else()
+    find_package(Zstd REQUIRED)
+  endif()
   if(Zstd_FOUND AND NOT Zstd_VERSION VERSION_LESS "1.0.0")
     set(HAVE_ZSTD ON)
+    if(TARGET zstd::libzstd_static) # prefer zstd CMake targets
+      list(APPEND CURL_LIBS zstd::libzstd_static)
+      message(STATUS "found zstd ${Zstd_VERSION}, linking against target zstd::libzstd_static")
+    elseif(TARGET zstd::libzstd_shared)
+      list(APPEND CURL_LIBS zstd::libzstd_shared)
+      message(STATUS "found zstd ${Zstd_VERSION}, linking against target zstd::libzstd_shared")
+    else() # no indent to keep diffs small
+      message(STATUS "found zstd ${Zstd_VERSION}, but no specific cmake target")
     list(APPEND CURL_LIBS ${Zstd_LIBRARIES})
     include_directories(${Zstd_INCLUDE_DIRS})
+    endif()
   else()
     message(WARNING "zstd v1.0.0 or newer is required, disabling zstd support.")
   endif()