More about 2011/richards and macOS

This includes a minor code change. I believe at this point that it's an
inherent issue of macOS but I might be wrong. I'll certainly look at
this more in the future but I'm going to try and work on the remaining
README.md files first. Time will tell how much I succeed.

2011/richards/Makefile

@@ -46,7 +46,7 @@ CWARN= -Wall -Wextra ${CSILENCE}
 
 # Compiler standard
 #
-CSTD= -std=gnu11
+CSTD= -std=gnu99
 
 # Compiler bit architecture
 #
@@ -65,7 +65,7 @@ CINCLUDE= -include stdlib.h -include string.h -include stdio.h -include ctype.h
 
 # Optimization
 #
-OPT= 
+OPT=
 
 # Default flags for ANSI C compilation
 #