Windows/Cygwin dlls need the executable bit set

CLA: trivial
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8226)

(cherry picked from commit fa63e45262971b9c2a6aeb33db8c52a5a84fc8b5)

Configurations/unix-Makefile.tmpl

@@ -651,7 +651,7 @@ install_runtime_libs: build_libs
 		: {- output_off() unless windowsdll(); "" -}; \
 		$(ECHO) "install $$s -> $(DESTDIR)$(INSTALLTOP)/bin/$$fn"; \
 		cp $$s $(DESTDIR)$(INSTALLTOP)/bin/$$fn.new; \
-		chmod 644 $(DESTDIR)$(INSTALLTOP)/bin/$$fn.new; \
+		chmod 755 $(DESTDIR)$(INSTALLTOP)/bin/$$fn.new; \
 		mv -f $(DESTDIR)$(INSTALLTOP)/bin/$$fn.new \
 		      $(DESTDIR)$(INSTALLTOP)/bin/$$fn; \
 		: {- output_on() unless windowsdll(); "" -}{- output_off() if windowsdll(); "" -}; \