docs: make .txt files over-writable when building from r/o sources

Otherwise an incremental build will fail to overwrite the destination
files.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/docs/Makefile b/docs/Makefile
index 46e8f2264a7a97c4c21579f5a6719bff592ccf61..2c0903b10ab08fbe7fac78e52a007ca116c95340 100644 (file)
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -124,7 +124,7 @@ endif
 
 html/%.txt: %.txt
        $(INSTALL_DIR) $(@D)
-       cp $< $@
+       $(INSTALL_DATA) $< $@
 
 html/man/%.1.html: man/%.pod.1 Makefile
        $(INSTALL_DIR) $(@D)