diff --git a/builds/posix/Makefile.in.extern.icu b/builds/posix/Makefile.in.extern.icu
index bec415502f..7346d7a651 100644
--- a/builds/posix/Makefile.in.extern.icu
+++ b/builds/posix/Makefile.in.extern.icu
@@ -33,10 +33,9 @@ include     $(ROOT)/gen/make.shared.variables
 .PHONY: libicu
 
 
-libicu: $(LIB)/libicuuc.so $(LIB)/libicudata.so $(LIB)/libicui18n.so
+libicu: $(LIB)/libicuuc.$(SHRLIB_EXT) $(LIB)/libicudata.$(SHRLIB_EXT) $(LIB)/libicui18n.$(SHRLIB_EXT)
 
-$(LIB)/libicuuc.so $(LIB)/libicudata.so $(LIB)/libicui18n.so:
-	cd $(ROOT)/extern/icu/source; chmod +x runConfigureICU configure install-sh; ./runConfigureICU @ICU_PLATFORM@ --prefix=`pwd`/..
+$(LIB)/libicuuc.$(SHRLIB_EXT) $(LIB)/libicudata.$(SHRLIB_EXT) $(LIB)/libicui18n.$(SHRLIB_EXT):
 	$(MAKE) -C $(ROOT)/extern/icu/source
 	$(MAKE) -C $(ROOT)/extern/icu/source install
 	cp $(ROOT)/extern/icu/lib/libicuuc* $(LIB)
diff --git a/configure.in b/configure.in
index 85d1fa334a..749064a68c 100644
--- a/configure.in
+++ b/configure.in
@@ -157,6 +157,7 @@ case "$target" in
     EDITLINE_FLG=N
     RAW_DEVICES_FLG=N
     SHRLIB_EXT=dll
+	ICU_PLATFORM=Cygwin
     ;;
 
   *)
@@ -986,6 +987,10 @@ gen/Makefile.extern.icu:${MAKE_SRC_DIR}/Makefile.in.extern.icu
 )
 AC_OUTPUT
 
+(cd extern/icu/source
+chmod +x runConfigureICU configure install-sh
+./runConfigureICU "$ICU_PLATFORM" --prefix=`pwd`/..)
+
 dnl Print out the build configuration (the most interesting thing)
 echo
 echo