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 

1 files changed, 91 insertions, 0 deletions

diff --git a/config/progtest.m4 b/config/progtest.m4
new file mode 100644
index 000000000..5f186b149
--- /dev/null
+++ b/config/progtest.m4
@@ -0,0 +1,91 @@
+# progtest.m4 serial 7 (gettext-0.18.2)
+dnl Copyright (C) 1996-2003, 2005, 2008-2019 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]>, 1996.
+
+AC_PREREQ([2.50])
+
+# Search path for a program which passes the given test.
+
+dnl AM_PATH_PROG_WITH_TEST(VARIABLE, PROG-TO-CHECK-FOR,
+dnl   TEST-PERFORMED-ON-FOUND_PROGRAM [, VALUE-IF-NOT-FOUND [, PATH]])
+AC_DEFUN([AM_PATH_PROG_WITH_TEST],
+[
+# Prepare PATH_SEPARATOR.
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  # Determine PATH_SEPARATOR by trying to find /bin/sh in a PATH which
+  # contains only /bin. Note that ksh looks also at the FPATH variable,
+  # so we have to set that as well for the test.
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+    && { (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
+           || PATH_SEPARATOR=';'
+       }
+fi
+
+# Find out how to test for executable files. Don't use a zero-byte file,
+# as systems may use methods other than mode bits to determine executability.
+cat >conf$$.file <<_ASEOF
+#! /bin/sh
+exit 0
+_ASEOF
+chmod +x conf$$.file
+if test -x conf$$.file >/dev/null 2>&1; then
+  ac_executable_p="test -x"
+else
+  ac_executable_p="test -f"
+fi
+rm -f conf$$.file
+
+# Extract the first word of "$2", so it can be a program name with args.
+set dummy $2; ac_word=[$]2
+AC_MSG_CHECKING([for $ac_word])
+AC_CACHE_VAL([ac_cv_path_$1],
+[case "[$]$1" in
+  [[\\/]]* | ?:[[\\/]]*)
+    ac_cv_path_$1="[$]$1" # Let the user override the test with a path.
+    ;;
+  *)
+    ac_save_IFS="$IFS"; IFS=$PATH_SEPARATOR
+    for ac_dir in ifelse([$5], , $PATH, [$5]); do
+      IFS="$ac_save_IFS"
+      test -z "$ac_dir" && ac_dir=.
+      for ac_exec_ext in '' $ac_executable_extensions; do
+        if $ac_executable_p "$ac_dir/$ac_word$ac_exec_ext"; then
+          echo "$as_me: trying $ac_dir/$ac_word..." >&AS_MESSAGE_LOG_FD
+          if [$3]; then
+            ac_cv_path_$1="$ac_dir/$ac_word$ac_exec_ext"
+            break 2
+          fi
+        fi
+      done
+    done
+    IFS="$ac_save_IFS"
+dnl If no 4th arg is given, leave the cache variable unset,
+dnl so AC_PATH_PROGS will keep looking.
+ifelse([$4], , , [  test -z "[$]ac_cv_path_$1" && ac_cv_path_$1="$4"
+])dnl
+    ;;
+esac])dnl
+$1="$ac_cv_path_$1"
+if test ifelse([$4], , [-n "[$]$1"], ["[$]$1" != "$4"]); then
+  AC_MSG_RESULT([$][$1])
+else
+  AC_MSG_RESULT([no])
+fi
+AC_SUBST([$1])dnl
+])