+dnl Define AM_ICONV using AC_DEFUN_ONCE for Autoconf >= 2.64, in order to
+dnl avoid warnings like
+dnl "warning: AC_REQUIRE: `AM_ICONV' was expanded before it was required".
+dnl This is tricky because of the way 'aclocal' is implemented:
+dnl - It requires defining an auxiliary macro whose name ends in AC_DEFUN.
+dnl Otherwise aclocal's initial scan pass would miss the macro definition.
+dnl - It requires a line break inside the AC_DEFUN_ONCE and AC_DEFUN expansions.
+dnl Otherwise aclocal would emit many "Use of uninitialized value $1"
+dnl warnings.
+m4_define([gl_iconv_AC_DEFUN],
+ m4_version_prereq([2.64],
+ [[AC_DEFUN_ONCE(
+ [$1], [$2])]],
+ [[AC_DEFUN(
+ [$1], [$2])]]))
+gl_iconv_AC_DEFUN([AM_ICONV],