diff --git a/CMakeLists.txt b/CMakeLists.txt
index 667f76e24b..3c9ab63bc9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -706,15 +706,13 @@ if(LYX_NLS)
 	endif()
 endif()
 
-if(UNIX)
-    find_package(ICONV REQUIRED)
-    find_package(ZLIB REQUIRED)
-else()
-    if(LYX_3RDPARTY_BUILD)
+if(LYX_3RDPARTY_BUILD)
 	add_subdirectory(3rdparty/libiconv)
 	set(HAVE_ICONV_CONST 1)
 	add_subdirectory(3rdparty/zlib)
-    endif()
+else()
+	find_package(ICONV REQUIRED)
+	find_package(ZLIB REQUIRED)
 endif()
 
 if(LYX_EXTERNAL_BOOST)