Use preserve mode to copy headers.
@@ -23,7 +23,7 @@ tests: lib
ifndef WINDOWS
install: no_test
mkdir -p $(DESTDIR)/include/mbedtls
- cp -r include/mbedtls $(DESTDIR)/include
+ cp -rp include/mbedtls $(DESTDIR)/include
mkdir -p $(DESTDIR)/lib
cp -RP library/libmbedtls.* $(DESTDIR)/lib
