Explicitly mention include interface dir for dependencies.
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 6c2f349..eea38b0 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -219,6 +219,7 @@
     PUBLIC
         $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/lib>
         $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}>
+	$<INSTALL_INTERFACE:include>
 )
 
 if(LIBZIP_DO_INSTALL)