patch 7.4.2111

Problem:    Defaults are very conservative.
Solution:   Move settings from vimrc_example.vim to defaults.vim.  Load
            defaults.vim if no .vimrc was found.

src/os_mac.h

@@ -139,6 +139,9 @@
 #ifndef SYS_OPTWIN_FILE
 #  define SYS_OPTWIN_FILE "$VIMRUNTIME/optwin.vim"
 #endif
+#ifndef VIM_DEFAULTS_FILE
+#  define VIM_DEFAULTS_FILE "$VIMRUNTIME/defaults.vim"
+#endif
 #ifndef EVIM_FILE
 #  define EVIM_FILE	"$VIMRUNTIME/evim.vim"
 #endif