Reword alt code suggestion in 1993/cmills

It is perhaps ironic, however, that we have managed to do this given
that in multiple platforms it only shows a blank screen (the original
too). This has been noted in bugs.md should anyone wish to try and fix
it.

Add -Wno-implicit-int to Makefile.

1993/cmills/Makefile

@@ -38,7 +38,7 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-return-type -Wno-deprecated-non-prototype
+CSILENCE= -Wno-return-type -Wno-deprecated-non-prototype -Wno-implicit-int
 
 # Common C compiler warning flags
 #

1993/cmills/README.md

@@ -1,24 +1,25 @@
 ## To build:
 
-We recommend you try the alt version first as with modern systems the original
-goes too fast. See the [original code](#original-code) section below to run the
-original.
-
+We recommend you try the alt version first so you can get a better idea of what
+this entry was like back in 1993. See the [original code](#original-code)
+section below to run the original.
 
 ```sh
 make alt
 ```
 
+NOTE: this entry requires the `X11/Xlib.h` header file and the X11 library to
+compile. If you're under macOS and do not know how to install and use X11
+programs see [FAQ 3.7  - How do I compile and use on macOS, an IOCCC winner that
+requires X11?](/faq.md#faq3_7).
+
+
 To configure how many microseconds to sleep before updates try:
 
 ```sh
 make clobber SLEEP=200 alt
 ```
 
-NOTE: this entry requires `X11/Xlib.h` header file and the X11 library to
-compile. macOS users running Mountain Lion and later will need to download and
-install [XQuartz](https://www.xquartz.org) in order to compile and run this
-entry.
 
 
 ### Bugs and (Mis)features:
@@ -45,6 +46,9 @@ where:
 `speed` is update speed from 1 to 9 (default is 9).
 
 
+NOTE: in most cases `DISPLAY` should already be set.
+
+
 ## Original code:
 
 We recommend the version that uses `usleep(3)` to more easily see what is going