Check in the pristine copy of ICU 4.6...

icu46/source/config/mh-unknown

Index: icu46/source/config/mh-unknown
===================================================================
--- icu46/source/config/mh-unknown	(revision 0)
+++ icu46/source/config/mh-unknown	(revision 0)
@@ -0,0 +1,27 @@
+## -*-makefile-*-
+## Copyright (c) 2003, International Business Machines Corporation and
+## others. All Rights Reserved.
+##
+
+# Note, this is not a real mh- file. You got here because configure
+# (specifically, aclocal.m4) could not determine a suitable mh- file.
+#
+# Perhaps your platform wasn't detected- try changing aclocal.m4 and
+# re-running autoconf. 
+#
+# If your platform is truly new/different:
+# As a start, try copying mh-linux (which is fairly generic) over this
+# file, and re-run config.status.
+
+%.$(STATIC_O) %.o %.$(STATIC_O) %.o ../data/%.o %.d %.d %.$(SO).$(SO_TARGET_VERSION_MAJOR) %.$(SO):
+	@echo 
+	@echo 
+	@echo "*** ERROR - configure could not detect your platform"
+	@echo "*** see the readme.html"
+	@echo "*** or, try copying icu/source/config/mh-linux to mh-unknown"
+	@echo "***   and editing it."
+	@echo 
+	@echo 
+	exit 1
+
+