diff -up ./CMakeLists.txt.el6 ./CMakeLists.txt
--- ./CMakeLists.txt.el6	2019-12-16 22:07:03.000000000 +0100
+++ ./CMakeLists.txt	2019-12-18 10:19:34.154147928 +0100
@@ -93,15 +93,6 @@ set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 project(${PROJECT_NAME} C)
 enable_testing()
 
-# POLICY
-# ------
-
-# The use of the word ZLIB_ROOT should still work prior to "3.12.0",
-# just it's been generalized for all packages now. Just set the policy
-# to new, so we use it, and it will be used prior to 3.12 anyway.
-if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.12")
-    cmake_policy(SET CMP0074 NEW)
-endif()
 
 # OPTIONS
 # -------
diff -up ./include/xlsxwriter/workbook.h.el6 ./include/xlsxwriter/workbook.h
--- ./include/xlsxwriter/workbook.h.el6	2019-12-18 10:19:34.154147928 +0100
+++ ./include/xlsxwriter/workbook.h	2019-12-18 10:20:44.277892402 +0100
@@ -937,11 +937,9 @@ void lxw_workbook_assemble_xml_file(lxw_
 void lxw_workbook_set_default_xf_indices(lxw_workbook *workbook);
 void workbook_unset_default_url_format(lxw_workbook *workbook);
 
-DEPRECATED(lxw_workbook *new_workbook(const char *filename),
-           "use 'workbook_new' instead");
-DEPRECATED(lxw_workbook *new_workbook_opt(const char *filename,
-                                          lxw_workbook_options *options),
-           "use 'workbook_new_opt()' instead");
+lxw_workbook *new_workbook(const char *filename);
+lxw_workbook *new_workbook_opt(const char *filename,
+                                          lxw_workbook_options *options);
 
 /* Declarations required for unit testing. */
 #ifdef TESTING