+dnl GUILE_LIBUNISTRING_WITH_ICONV_SUPPORT
+dnl
+dnl Check whether libunistring has iconv support. When it lacks iconv
+dnl support, `mem_iconveh' returns -1 (ENOSYS) and conversions from one
+dnl codeset to another do not work.
+AC_DEFUN([GUILE_LIBUNISTRING_WITH_ICONV_SUPPORT], [
+ AC_CACHE_CHECK([whether libunistring was built with iconv support],
+ [ac_cv_libunistring_with_iconv_support], [
+ save_LIBS=$LIBS
+ LIBS="$LIBS $LIBUNISTRING"
+ AC_RUN_IFELSE([AC_LANG_SOURCE([[
+ #include <uniconv.h>
+ #include <unistring/iconveh.h>
+ int
+ main (int argc, char *argv[])
+ {
+ size_t result_size;
+ return (NULL == u32_conv_from_encoding ("ASCII", iconveh_question_mark,
+ "a", 1,
+ NULL, NULL, &result_size));
+ }
+ ]])],
+ [ac_cv_libunistring_with_iconv_support=yes],
+ [ac_cv_libunistring_with_iconv_support=no],
+ [ac_cv_libunistring_with_iconv_support=yes])
+ LIBS=$save_LIBS
+ ])
+])
+
+dnl GUILE_UNISTRING_CONSTANT NAME
+dnl
+dnl Determine the compile-time value of NAME and define/substitute
+dnl `SCM_I_GSC_NAME'.
+AC_DEFUN([GUILE_UNISTRING_CONSTANT], [
+ m4_pushdef([UPPER_CASE_NAME],
+ [m4_translit([$1],[abcdefghijklmnopqrstuvwxyz],
+ [ABCDEFGHIJKLMNOPQRSTUVWXYZ])])
+
+ AC_CACHE_CHECK([the value of `$1'], [ac_cv_]$1, [
+ AC_COMPUTE_INT([ac_cv_]$1, [$1],
+ [AC_INCLUDES_DEFAULT
+#include <uniconv.h>
+],
+ [AC_MSG_ERROR([failed to determine the value of `$1'])])
+ ])
+
+ [SCM_I_GSC_]UPPER_CASE_NAME="$ac_cv_[]$1"
+ AC_SUBST([SCM_I_GSC_]UPPER_CASE_NAME)
+ m4_popdef([UPPER_CASE_NAME])])
+
+dnl GUILE_UNISTRING_ICONVEH_VALUES
+dnl
+dnl Determine the values of the `iconveh_' libunistring constants.
+AC_DEFUN([GUILE_UNISTRING_ICONVEH_VALUES], [
+ GUILE_UNISTRING_CONSTANT([iconveh_error])
+ GUILE_UNISTRING_CONSTANT([iconveh_question_mark])
+ GUILE_UNISTRING_CONSTANT([iconveh_escape_sequence])