assume GNU gettext >= 0.17

[Bruno Haible <bruno@clisp.org>]

gnulib-tool emits a couple of notices that start with
"If you are using GNU gettext version 0.16.1 or older ..."

GNU gettext 0.17 was released in 2007, and according to
<https://repology.org/project/gettext/versions> all distros
(even CentOS 6) ship this version at least. So, by now we can
assume that everyone is using version 0.17 at least.

The user does not need to set XGETTEXT_OPTIONS for things that
AM_XGETTEXT_OPTION arranges for, automatically.


2021-07-25  Bruno Haible  <bruno@clisp.org>

	Assume GNU gettext >= 0.17.
	* modules/vasprintf (Notice): Remove.
	* modules/xvasprintf (Notice): Remove.
	* modules/xprintf (Notice): Remove.
	* modules/error (Notice): Remove.
	* modules/verror (Notice): Remove.
	* modules/argp (Notice): Remove.
	* modules/propername (Notice): Remove.
	* lib/propername.h: Remove outdated comment.

diff --git a/lib/propername.h b/lib/propername.h
index 8037de7..ee09d7c 100644
--- a/lib/propername.h
+++ b/lib/propername.h
@@ -51,7 +51,7 @@
    output will look like this:
       <translated name> (<original name in English>)
 
-   To use the 'propername' module requires three simple steps:
+   To use the 'propername' module requires two simple steps:
 
      1) Add it to the list of gnulib modules to import,
 
@@ -68,16 +68,6 @@
 
         (Optionally, here you can also add / * TRANSLATORS: ... * / comments
         explaining how the name is written or pronounced.)
-
-     3) If you are using GNU gettext version 0.16.1 or older, in po/Makevars,
-        in the definition of the XGETTEXT_OPTIONS variable, add:
-
-           --keyword='proper_name:1,"This is a proper name. See the gettext manual, section Names."'
-           --keyword='proper_name_utf8:1,"This is a proper name. See the gettext manual, section Names."'
-
-        This specifies automatic comments for the translator. (Requires
-        xgettext >= 0.15. The double-quotes inside the quoted string are on
-        purpose: they are part of the --keyword argument syntax.)
  */
 
 #ifndef _PROPERNAME_H
diff --git a/modules/argp b/modules/argp
index 38a7905..85eefe2 100644
--- a/modules/argp
+++ b/modules/argp
@@ -1,11 +1,6 @@
 Description:
 Hierarchical processing of command line arguments.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --flag=argp_error:2:c-format --flag=argp_failure:4:c-format
-
 Files:
 lib/argp.h
 lib/argp-ba.c
diff --git a/modules/error b/modules/error
index a0fb4c0..2945c48 100644
--- a/modules/error
+++ b/modules/error
@@ -1,11 +1,6 @@
 Description:
 error and error_at_line functions: Error reporting.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --flag=error:3:c-format --flag=error_at_line:5:c-format
-
 Files:
 lib/error.h
 lib/error.c
diff --git a/modules/propername b/modules/propername
index ab06a46..fb1e78a 100644
--- a/modules/propername
+++ b/modules/propername
@@ -1,12 +1,6 @@
 Description:
 Localization of proper names.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --keyword='proper_name:1,"This is a proper name. See the gettext manual, section Names."'
-  --keyword='proper_name_utf8:1,"This is a proper name. See the gettext manual, section Names."'
-
 Files:
 lib/propername.h
 lib/propername.c
diff --git a/modules/vasprintf b/modules/vasprintf
index 59e5a86..91d082b 100644
--- a/modules/vasprintf
+++ b/modules/vasprintf
@@ -1,11 +1,6 @@
 Description:
 vsprintf with automatic memory allocation.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --flag=asprintf:2:c-format --flag=vasprintf:2:c-format
-
 Files:
 lib/vasprintf.c
 lib/asprintf.c
diff --git a/modules/verror b/modules/verror
index e183f68..16ad0c5 100644
--- a/modules/verror
+++ b/modules/verror
@@ -1,11 +1,6 @@
 Description:
 verror and verror_at_line functions: Error reporting with va_list.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --flag=verror:3:c-format --flag=verror_at_line:5:c-format
-
 Files:
 lib/verror.h
 lib/verror.c
diff --git a/modules/xprintf b/modules/xprintf
index de61260..f4942ce 100644
--- a/modules/xprintf
+++ b/modules/xprintf
@@ -1,12 +1,6 @@
 Description:
 a wrapper around printf that calls error upon ENOMEM or EILSEQ errors
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars:
-  --flag=xprintf:1:c-format --flag=xvprintf:1:c-format
-  --flag=xfprintf:2:c-format --flag=xvfprintf:2:c-format
-
 Files:
 lib/xprintf.h
 lib/xprintf.c
diff --git a/modules/xvasprintf b/modules/xvasprintf
index 373c1fa..ae23314 100644
--- a/modules/xvasprintf
+++ b/modules/xvasprintf
@@ -1,10 +1,6 @@
 Description:
 vasprintf and asprintf with out-of-memory checking.  Also see xalloc-die.
 
-Notice:
-If you are using GNU gettext version 0.16.1 or older, add the following options
-to XGETTEXT_OPTIONS in your po/Makevars: --flag=xasprintf:1:c-format
-
 Files:
 lib/xvasprintf.h
 lib/xvasprintf.c