diff --git a/m4/ax_check_icu.m4 b/m4/ax_check_icu.m4
new file mode 100644
index 00000000..96b2b298
--- /dev/null
+++ b/m4/ax_check_icu.m4
@@ -0,0 +1,116 @@
+# ===========================================================================
+#       https://www.gnu.org/software/autoconf-archive/ax_check_icu.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_ICU(version, action-if, action-if-not)
+#
+# DESCRIPTION
+#
+#   Defines ICU_LIBS, ICU_CFLAGS, ICU_CXXFLAGS. See icu-config(1) man page.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Akos Maroy <darkeye@tyrell.hu>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 7
+
+AC_DEFUN([AX_CHECK_ICU], [
+  succeeded=no
+
+  if test -z "$ICU_CONFIG"; then
+    AC_PATH_PROG(ICU_CONFIG, icu-config, no)
+  fi
+
+  if test -z "$PKG_CONFIG"; then
+    AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
+  fi
+
+  if test "$ICU_CONFIG" = "no" && test "$PKG_CONFIG" = "no" ; then
+    echo "*** Neither icu-config nor pkg-config could not be found. Make sure either is"
+    echo "*** in your path, and that taglib is properly installed."
+    echo "*** Or see http://ibm.com/software/globalization/icu/"
+  fi
+
+  if test "$ICU_CONFIG" != "no" ; then
+    ICU_VERSION=`$ICU_CONFIG --version`
+    AC_MSG_CHECKING(for ICU >= $1 via icu-config)
+        VERSION_CHECK=`expr $ICU_VERSION \>\= $1`
+        if test "$VERSION_CHECK" = "1" ; then
+            AC_MSG_RESULT(yes)
+            succeeded=yes
+
+            AC_MSG_CHECKING(ICU_CPPFLAGS)
+            ICU_CPPFLAGS=`$ICU_CONFIG --cppflags`
+            AC_MSG_RESULT($ICU_CPPFLAGS)
+
+            AC_MSG_CHECKING(ICU_CFLAGS)
+            ICU_CFLAGS=`$ICU_CONFIG --cflags`
+            AC_MSG_RESULT($ICU_CFLAGS)
+
+            AC_MSG_CHECKING(ICU_CXXFLAGS)
+            ICU_CXXFLAGS=`$ICU_CONFIG --cxxflags`
+            AC_MSG_RESULT($ICU_CXXFLAGS)
+
+            AC_MSG_CHECKING(ICU_LIBS)
+            ICU_LIBS=`$ICU_CONFIG --ldflags`
+            AC_MSG_RESULT($ICU_LIBS)
+        else
+            ICU_CPPFLAGS=""
+            ICU_CFLAGS=""
+            ICU_CXXFLAGS=""
+            ICU_LIBS=""
+            ## If we have a custom action on failure, don't print errors, but
+            ## do set a variable so people can do so.
+            ifelse([$3], ,echo "can't find ICU >= $1 via icu-config",)
+        fi
+  fi
+
+  if test "$succeeded" != "yes" && test "$PKG_CONFIG" != "no" ; then
+    AC_MSG_CHECKING(for ICU >= $1 via pkg-config)
+        if $PKG_CONFIG --atleast-version=$1 icu-i18n ; then
+            AC_MSG_RESULT(yes)
+            succeeded=yes
+
+            AC_MSG_CHECKING(ICU_CPPFLAGS)
+            ICU_CPPFLAGS=`$PKG_CONFIG --variable=CPPFLAGS icu-i18n`
+            AC_MSG_RESULT($ICU_CPPFLAGS)
+
+            AC_MSG_CHECKING(ICU_CFLAGS)
+            ICU_CFLAGS=`$PKG_CONFIG --cflags icu-i18n`
+            AC_MSG_RESULT($ICU_CFLAGS)
+
+            AC_MSG_CHECKING(ICU_CXXFLAGS)
+            ICU_CXXFLAGS=`$PKG_CONFIG --variable=CXXFLAGS icu-i18n`
+            AC_MSG_RESULT($ICU_CXXFLAGS)
+
+            AC_MSG_CHECKING(ICU_LIBS)
+            ICU_LIBS=`$PKG_CONFIG --libs icu-i18n`
+            AC_MSG_RESULT($ICU_LIBS)
+        else
+            ICU_CPPFLAGS=""
+            ICU_CFLAGS=""
+            ICU_CXXFLAGS=""
+            ICU_LIBS=""
+            ## If we have a custom action on failure, don't print errors, but
+            ## do set a variable so people can do so.
+            ifelse([$3], ,echo "can't find ICU >= $1 via pkg-config",)
+        fi
+  fi
+
+  if test "$succeeded" = "yes"; then
+     AC_SUBST(ICU_CPPFLAGS)
+     AC_SUBST(ICU_CFLAGS)
+     AC_SUBST(ICU_CXXFLAGS)
+     AC_SUBST(ICU_LIBS)
+     ifelse([$2], , :, [$2])
+  else
+     ifelse([$3], , AC_MSG_ERROR([Library requirements (ICU) not met.]), [$3])
+  fi
+])