config: libintl/libiconv for gettext() detection

Detect in autoconf whether `-lintl` and possibly `-liconv` are necessary
for translation functions like `gettext()`.

The actual autoconf code is just:

```
AM_ICONV
AM_GNU_GETTEXT([external])
LIBS="$LIBS $LTLIBINTL $LTLIBICONV"
```

References:

https://www.gnu.org/software/gettext/manual/html_node/AM_005fGNU_005fGETTEXT.html
https://www.gnu.org/software/gettext/manual/html_node/AM_005fICONV.html

The reason to check for `libiconv` and add it separately is that this is
sometimes necessary if users are linking statically.

The `config/*.m4` files were added by running `gettextize` and removing
everything else.

The empty file `config/config.rpath` is necessary to avoid an error with
some versions of autotools, see:

http://ramblingfoo.blogspot.com/2007/07/required-file-configrpath-not-found.html

The `config.rpath` copied by `gettextize` does not currently work, there
is some kind of missing interaction with `libtool` and it tries to apply
`libtool` flags to the compiler.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Richard Laager <[email protected]>
Signed-off-by: Rafael Kitover <[email protected]>
Closes #8554

config/gettext.m4

@@ -0,0 +1,386 @@
+# gettext.m4 serial 70 (gettext-0.20)
+dnl Copyright (C) 1995-2014, 2016, 2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl
+dnl This file can be used in projects which are not available under
+dnl the GNU General Public License or the GNU Library General Public
+dnl License but which still want to provide support for the GNU gettext
+dnl functionality.
+dnl Please note that the actual code of the GNU gettext library is covered
+dnl by the GNU Library General Public License, and the rest of the GNU
+dnl gettext package is covered by the GNU General Public License.
+dnl They are *not* in the public domain.
+
+dnl Authors:
+dnl   Ulrich Drepper <[email protected]>, 1995-2000.
+dnl   Bruno Haible <[email protected]>, 2000-2006, 2008-2010.
+
+dnl Macro to add for using GNU gettext.
+
+dnl Usage: AM_GNU_GETTEXT([INTLSYMBOL], [NEEDSYMBOL], [INTLDIR]).
+dnl INTLSYMBOL must be one of 'external', 'use-libtool'.
+dnl    INTLSYMBOL should be 'external' for packages other than GNU gettext, and
+dnl    'use-libtool' for the packages 'gettext-runtime' and 'gettext-tools'.
+dnl    If INTLSYMBOL is 'use-libtool', then a libtool library
+dnl    $(top_builddir)/intl/libintl.la will be created (shared and/or static,
+dnl    depending on --{enable,disable}-{shared,static} and on the presence of
+dnl    AM-DISABLE-SHARED).
+dnl If NEEDSYMBOL is specified and is 'need-ngettext', then GNU gettext
+dnl    implementations (in libc or libintl) without the ngettext() function
+dnl    will be ignored.  If NEEDSYMBOL is specified and is
+dnl    'need-formatstring-macros', then GNU gettext implementations that don't
+dnl    support the ISO C 99 <inttypes.h> formatstring macros will be ignored.
+dnl INTLDIR is used to find the intl libraries.  If empty,
+dnl    the value '$(top_builddir)/intl/' is used.
+dnl
+dnl The result of the configuration is one of three cases:
+dnl 1) GNU gettext, as included in the intl subdirectory, will be compiled
+dnl    and used.
+dnl    Catalog format: GNU --> install in $(datadir)
+dnl    Catalog extension: .mo after installation, .gmo in source tree
+dnl 2) GNU gettext has been found in the system's C library.
+dnl    Catalog format: GNU --> install in $(datadir)
+dnl    Catalog extension: .mo after installation, .gmo in source tree
+dnl 3) No internationalization, always use English msgid.
+dnl    Catalog format: none
+dnl    Catalog extension: none
+dnl If INTLSYMBOL is 'external', only cases 2 and 3 can occur.
+dnl The use of .gmo is historical (it was needed to avoid overwriting the
+dnl GNU format catalogs when building on a platform with an X/Open gettext),
+dnl but we keep it in order not to force irrelevant filename changes on the
+dnl maintainers.
+dnl
+AC_DEFUN([AM_GNU_GETTEXT],
+[
+  dnl Argument checking.
+  ifelse([$1], [], , [ifelse([$1], [external], , [ifelse([$1], [use-libtool], ,
+    [errprint([ERROR: invalid first argument to AM_GNU_GETTEXT
+])])])])
+  ifelse(ifelse([$1], [], [old])[]ifelse([$1], [no-libtool], [old]), [old],
+    [errprint([ERROR: Use of AM_GNU_GETTEXT without [external] argument is no longer supported.
+])])
+  ifelse([$2], [], , [ifelse([$2], [need-ngettext], , [ifelse([$2], [need-formatstring-macros], ,
+    [errprint([ERROR: invalid second argument to AM_GNU_GETTEXT
+])])])])
+  define([gt_included_intl],
+    ifelse([$1], [external], [no], [yes]))
+  gt_NEEDS_INIT
+  AM_GNU_GETTEXT_NEED([$2])
+
+  AC_REQUIRE([AM_PO_SUBDIRS])dnl
+  ifelse(gt_included_intl, yes, [
+    AC_REQUIRE([AM_INTL_SUBDIR])dnl
+  ])
+
+  dnl Prerequisites of AC_LIB_LINKFLAGS_BODY.
+  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
+  AC_REQUIRE([AC_LIB_RPATH])
+
+  dnl Sometimes libintl requires libiconv, so first search for libiconv.
+  dnl Ideally we would do this search only after the
+  dnl      if test "$USE_NLS" = "yes"; then
+  dnl        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" != "yes"; }; then
+  dnl tests. But if configure.in invokes AM_ICONV after AM_GNU_GETTEXT
+  dnl the configure script would need to contain the same shell code
+  dnl again, outside any 'if'. There are two solutions:
+  dnl - Invoke AM_ICONV_LINKFLAGS_BODY here, outside any 'if'.
+  dnl - Control the expansions in more detail using AC_PROVIDE_IFELSE.
+  dnl Since AC_PROVIDE_IFELSE is not documented, we avoid it.
+  ifelse(gt_included_intl, yes, , [
+    AC_REQUIRE([AM_ICONV_LINKFLAGS_BODY])
+  ])
+
+  dnl Sometimes, on Mac OS X, libintl requires linking with CoreFoundation.
+  gt_INTL_MACOSX
+
+  dnl Set USE_NLS.
+  AC_REQUIRE([AM_NLS])
+
+  ifelse(gt_included_intl, yes, [
+    BUILD_INCLUDED_LIBINTL=no
+    USE_INCLUDED_LIBINTL=no
+  ])
+  LIBINTL=
+  LTLIBINTL=
+  POSUB=
+
+  dnl Add a version number to the cache macros.
+  case " $gt_needs " in
+    *" need-formatstring-macros "*) gt_api_version=3 ;;
+    *" need-ngettext "*) gt_api_version=2 ;;
+    *) gt_api_version=1 ;;
+  esac
+  gt_func_gnugettext_libc="gt_cv_func_gnugettext${gt_api_version}_libc"
+  gt_func_gnugettext_libintl="gt_cv_func_gnugettext${gt_api_version}_libintl"
+
+  dnl If we use NLS figure out what method
+  if test "$USE_NLS" = "yes"; then
+    gt_use_preinstalled_gnugettext=no
+    ifelse(gt_included_intl, yes, [
+      AC_MSG_CHECKING([whether included gettext is requested])
+      AC_ARG_WITH([included-gettext],
+        [  --with-included-gettext use the GNU gettext library included here],
+        nls_cv_force_use_gnu_gettext=$withval,
+        nls_cv_force_use_gnu_gettext=no)
+      AC_MSG_RESULT([$nls_cv_force_use_gnu_gettext])
+
+      nls_cv_use_gnu_gettext="$nls_cv_force_use_gnu_gettext"
+      if test "$nls_cv_force_use_gnu_gettext" != "yes"; then
+    ])
+        dnl User does not insist on using GNU NLS library.  Figure out what
+        dnl to use.  If GNU gettext is available we use this.  Else we have
+        dnl to fall back to GNU NLS library.
+
+        if test $gt_api_version -ge 3; then
+          gt_revision_test_code='
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+#define __GNU_GETTEXT_SUPPORTED_REVISION(major) ((major) == 0 ? 0 : -1)
+#endif
+changequote(,)dnl
+typedef int array [2 * (__GNU_GETTEXT_SUPPORTED_REVISION(0) >= 1) - 1];
+changequote([,])dnl
+'
+        else
+          gt_revision_test_code=
+        fi
+        if test $gt_api_version -ge 2; then
+          gt_expression_test_code=' + * ngettext ("", "", 0)'
+        else
+          gt_expression_test_code=
+        fi
+
+        AC_CACHE_CHECK([for GNU gettext in libc], [$gt_func_gnugettext_libc],
+         [AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[
+#include <libintl.h>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern int *_nl_domain_bindings;
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_domain_bindings)
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+               ]],
+               [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+               ]])],
+            [eval "$gt_func_gnugettext_libc=yes"],
+            [eval "$gt_func_gnugettext_libc=no"])])
+
+        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" != "yes"; }; then
+          dnl Sometimes libintl requires libiconv, so first search for libiconv.
+          ifelse(gt_included_intl, yes, , [
+            AM_ICONV_LINK
+          ])
+          dnl Search for libintl and define LIBINTL, LTLIBINTL and INCINTL
+          dnl accordingly. Don't use AC_LIB_LINKFLAGS_BODY([intl],[iconv])
+          dnl because that would add "-liconv" to LIBINTL and LTLIBINTL
+          dnl even if libiconv doesn't exist.
+          AC_LIB_LINKFLAGS_BODY([intl])
+          AC_CACHE_CHECK([for GNU gettext in libintl],
+            [$gt_func_gnugettext_libintl],
+           [gt_save_CPPFLAGS="$CPPFLAGS"
+            CPPFLAGS="$CPPFLAGS $INCINTL"
+            gt_save_LIBS="$LIBS"
+            LIBS="$LIBS $LIBINTL"
+            dnl Now see whether libintl exists and does not depend on libiconv.
+            AC_LINK_IFELSE(
+              [AC_LANG_PROGRAM(
+                 [[
+#include <libintl.h>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+                 ]],
+                 [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+                 ]])],
+              [eval "$gt_func_gnugettext_libintl=yes"],
+              [eval "$gt_func_gnugettext_libintl=no"])
+            dnl Now see whether libintl exists and depends on libiconv.
+            if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" != yes; } && test -n "$LIBICONV"; then
+              LIBS="$LIBS $LIBICONV"
+              AC_LINK_IFELSE(
+                [AC_LANG_PROGRAM(
+                   [[
+#include <libintl.h>
+#ifndef __GNU_GETTEXT_SUPPORTED_REVISION
+extern int _nl_msg_cat_cntr;
+extern
+#ifdef __cplusplus
+"C"
+#endif
+const char *_nl_expand_alias (const char *);
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION (_nl_msg_cat_cntr + *_nl_expand_alias (""))
+#else
+#define __GNU_GETTEXT_SYMBOL_EXPRESSION 0
+#endif
+$gt_revision_test_code
+                   ]],
+                   [[
+bindtextdomain ("", "");
+return * gettext ("")$gt_expression_test_code + __GNU_GETTEXT_SYMBOL_EXPRESSION
+                   ]])],
+                [LIBINTL="$LIBINTL $LIBICONV"
+                 LTLIBINTL="$LTLIBINTL $LTLIBICONV"
+                 eval "$gt_func_gnugettext_libintl=yes"
+                ])
+            fi
+            CPPFLAGS="$gt_save_CPPFLAGS"
+            LIBS="$gt_save_LIBS"])
+        fi
+
+        dnl If an already present or preinstalled GNU gettext() is found,
+        dnl use it.  But if this macro is used in GNU gettext, and GNU
+        dnl gettext is already preinstalled in libintl, we update this
+        dnl libintl.  (Cf. the install rule in intl/Makefile.in.)
+        if { eval "gt_val=\$$gt_func_gnugettext_libc"; test "$gt_val" = "yes"; } \
+           || { { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; } \
+                && test "$PACKAGE" != gettext-runtime \
+                && test "$PACKAGE" != gettext-tools; }; then
+          gt_use_preinstalled_gnugettext=yes
+        else
+          dnl Reset the values set by searching for libintl.
+          LIBINTL=
+          LTLIBINTL=
+          INCINTL=
+        fi
+
+    ifelse(gt_included_intl, yes, [
+        if test "$gt_use_preinstalled_gnugettext" != "yes"; then
+          dnl GNU gettext is not found in the C library.
+          dnl Fall back on included GNU gettext library.
+          nls_cv_use_gnu_gettext=yes
+        fi
+      fi
+
+      if test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Mark actions used to generate GNU NLS library.
+        BUILD_INCLUDED_LIBINTL=yes
+        USE_INCLUDED_LIBINTL=yes
+        LIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.la $LIBICONV $LIBTHREAD"
+        LTLIBINTL="ifelse([$3],[],\${top_builddir}/intl,[$3])/libintl.la $LTLIBICONV $LTLIBTHREAD"
+        LIBS=`echo " $LIBS " | sed -e 's/ -lintl / /' -e 's/^ //' -e 's/ $//'`
+      fi
+
+      CATOBJEXT=
+      if test "$gt_use_preinstalled_gnugettext" = "yes" \
+         || test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Mark actions to use GNU gettext tools.
+        CATOBJEXT=.gmo
+      fi
+    ])
+
+    if test -n "$INTL_MACOSX_LIBS"; then
+      if test "$gt_use_preinstalled_gnugettext" = "yes" \
+         || test "$nls_cv_use_gnu_gettext" = "yes"; then
+        dnl Some extra flags are needed during linking.
+        LIBINTL="$LIBINTL $INTL_MACOSX_LIBS"
+        LTLIBINTL="$LTLIBINTL $INTL_MACOSX_LIBS"
+      fi
+    fi
+
+    if test "$gt_use_preinstalled_gnugettext" = "yes" \
+       || test "$nls_cv_use_gnu_gettext" = "yes"; then
+      AC_DEFINE([ENABLE_NLS], [1],
+        [Define to 1 if translation of program messages to the user's native language
+   is requested.])
+    else
+      USE_NLS=no
+    fi
+  fi
+
+  AC_MSG_CHECKING([whether to use NLS])
+  AC_MSG_RESULT([$USE_NLS])
+  if test "$USE_NLS" = "yes"; then
+    AC_MSG_CHECKING([where the gettext function comes from])
+    if test "$gt_use_preinstalled_gnugettext" = "yes"; then
+      if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; }; then
+        gt_source="external libintl"
+      else
+        gt_source="libc"
+      fi
+    else
+      gt_source="included intl directory"
+    fi
+    AC_MSG_RESULT([$gt_source])
+  fi
+
+  if test "$USE_NLS" = "yes"; then
+
+    if test "$gt_use_preinstalled_gnugettext" = "yes"; then
+      if { eval "gt_val=\$$gt_func_gnugettext_libintl"; test "$gt_val" = "yes"; }; then
+        AC_MSG_CHECKING([how to link with libintl])
+        AC_MSG_RESULT([$LIBINTL])
+        AC_LIB_APPENDTOVAR([CPPFLAGS], [$INCINTL])
+      fi
+
+      dnl For backward compatibility. Some packages may be using this.
+      AC_DEFINE([HAVE_GETTEXT], [1],
+       [Define if the GNU gettext() function is already present or preinstalled.])
+      AC_DEFINE([HAVE_DCGETTEXT], [1],
+       [Define if the GNU dcgettext() function is already present or preinstalled.])
+    fi
+
+    dnl We need to process the po/ directory.
+    POSUB=po
+  fi
+
+  ifelse(gt_included_intl, yes, [
+    dnl In GNU gettext we have to set BUILD_INCLUDED_LIBINTL to 'yes'
+    dnl because some of the testsuite requires it.
+    BUILD_INCLUDED_LIBINTL=yes
+
+    dnl Make all variables we use known to autoconf.
+    AC_SUBST([BUILD_INCLUDED_LIBINTL])
+    AC_SUBST([USE_INCLUDED_LIBINTL])
+    AC_SUBST([CATOBJEXT])
+  ])
+
+  dnl For backward compatibility. Some Makefiles may be using this.
+  INTLLIBS="$LIBINTL"
+  AC_SUBST([INTLLIBS])
+
+  dnl Make all documented variables known to autoconf.
+  AC_SUBST([LIBINTL])
+  AC_SUBST([LTLIBINTL])
+  AC_SUBST([POSUB])
+])
+
+
+dnl gt_NEEDS_INIT ensures that the gt_needs variable is initialized.
+m4_define([gt_NEEDS_INIT],
+[
+  m4_divert_text([DEFAULTS], [gt_needs=])
+  m4_define([gt_NEEDS_INIT], [])
+])
+
+
+dnl Usage: AM_GNU_GETTEXT_NEED([NEEDSYMBOL])
+AC_DEFUN([AM_GNU_GETTEXT_NEED],
+[
+  m4_divert_text([INIT_PREPARE], [gt_needs="$gt_needs $1"])
+])
+
+
+dnl Usage: AM_GNU_GETTEXT_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_VERSION], [])
+
+
+dnl Usage: AM_GNU_GETTEXT_REQUIRE_VERSION([gettext-version])
+AC_DEFUN([AM_GNU_GETTEXT_REQUIRE_VERSION], [])