re6st: fix build of gettext

Since debian/compat is increased to 9, stricter flags are used for compilation.

With default dpkg-buildflags, gettext fails to build as follows:

libcroco/cr-statement.c: In function 'cr_statement_dump_ruleset':
libcroco/cr-statement.c:2610:17: error: format not a string literal and no format arguments [-Werror=format-security]
                 fprintf (a_fp, str);
                 ^

obs/re6st/README

@@ -23,7 +23,7 @@ pointing to it. For example, the vifib test directory::
 And whenever you want to push updates::
 
   A$ ./make osc
-  A$ (cd osc; osc commit)
+  A$ (cd osc && osc commit)
 
 Warning about SlapOS updates
 ----------------------------

obs/re6st/debian/rules

@@ -2,6 +2,9 @@
 # -*- makefile -*-
 #export DH_VERBOSE=1
 
+# WKRD: gettext
+export DEB_BUILD_MAINT_OPTIONS = hardening=-format
+
 include debian/common.mk
 
 override_dh_auto_install: