Don't strip static libraries.

Index: source/io/Makefile.in
--- source/io/Makefile.in.orig
+++ source/io/Makefile.in
@@ -97,7 +97,7 @@ install-local: install-headers install-library
 install-library: all-local
 	$(MKINSTALLDIRS) $(DESTDIR)$(libdir)
 ifneq ($(ENABLE_STATIC),)
-	$(INSTALL-L) $(TARGET) $(DESTDIR)$(libdir)
+	$(INSTALL_DATA) $(TARGET) $(DESTDIR)$(libdir)
 endif
 ifneq ($(ENABLE_SHARED),)
 # For MinGW, do we want the DLL to go in the bin location?