- Fix dependencies and remove old default_options.h from version control

- Rename default_options.h.in -> default_options.h, and
  default_options.h -> default_options_guard.h
- Fix newlines in default_options.h

ifndef_wrapper.sh

@@ -2,6 +2,6 @@
 
 # Wrap all "#define X Y" with a #ifndef X...#endif"
 
-sed -E 's/^(#define ([^ ]+) .*)/#ifndef \2\
+sed -E 's/^( *#define ([^ ]+) .*)/#ifndef \2\
 \1\
 #endif/'