diff -r a2940bea3a6d -r 60635dc58066 Makefile
--- a/Makefile	Thu Nov 29 00:00:11 2018 +0200
+++ b/Makefile	Wed Dec 12 12:45:40 2018 +0200
@@ -36,9 +36,9 @@
 ################################################################
 # Build tool definition/switches.
 
-INSTALL_DATA := install -m 640
+INSTALL_DATA := install -m 640 -D
 ifeq '$(host_os)' 'solaris'
-  INSTALL_DATA := ginstall -m 640
+  INSTALL_DATA := ginstall -m 640 -D
 endif
 
 RST2HTML = rst2html