Unix: Set the execute permission on installed shared libraries

Some Unix variants require shared libraries to have the execute
permissions set, or they won't be loadable or executable when loaded.
Among others, cygwin has this requirement.
Reviewed-by: NMatt Caswell <matt@openssl.org>

Configurations/unix-Makefile.tmpl

@@ -368,7 +368,7 @@ install_dev:
 		: {- output_off() if windowsdll(); "" -}; \
 		echo "install $$s1 -> $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1"; \
 		cp $$s1 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1.new; \
-		chmod 644 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1.new; \
+		chmod 755 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1.new; \
 		mv -f $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1.new \
 		      $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn1; \
 		if [ "$$fn1" != "$$fn2" ]; then \
@@ -378,7 +378,7 @@ install_dev:
 		: {- output_on() if windowsdll(); "" -}{- output_off() unless windowsdll(); "" -}; \
 		echo "install $$s2 -> $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2"; \
 		cp $$s2 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2.new; \
-		chmod 644 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2.new; \
+		chmod 755 $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2.new; \
 		mv -f $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2.new \
 		      $(DESTDIR)$(INSTALLTOP)/$(LIBDIR)/$$fn2; \
 		: {- output_on() unless windowsdll(); "" -}; \