patch 8.1.2402: typos and other small things

Problem:    Typos and other small things.
Solution:   Small fixes.
diff --git a/src/Makefile b/src/Makefile
index fb232b1..067110a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -413,9 +413,11 @@
 
 # MZSCHEME
 # Uncomment this when you want to include the MzScheme interface.
+# You may have to build racket from source to make this work.
 # NOTE: does not work well together with valgrind.
 #CONF_OPT_MZSCHEME = --enable-mzschemeinterp
 # PLT/mrscheme/drscheme Home dir; the PLTHOME environment variable also works
+#CONF_OPT_PLTHOME  = --with-plthome=/usr/local
 #CONF_OPT_PLTHOME  = --with-plthome=/usr/local/plt
 #CONF_OPT_PLTHOME  = --with-plthome=/usr/local/drscheme
 #CONF_OPT_PLTHOME  = --with-plthome=/home/me/mz
@@ -612,7 +614,7 @@
 # Use this with GCC to check for mistakes, unused arguments, etc.
 # Note: If you use -Wextra and get warnings in GTK code about function
 #       parameters, you can add -Wno-cast-function-type
-#CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wunreachable-code -Wno-cast-function-type -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
+#CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wunreachable-code -Wno-cast-function-type -Wno-deprecated-declarations -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
 # Add -Wpedantic to find // comments and other C99 constructs.
 # Better disable Perl and Python to avoid a lot of warnings.
 #CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wpedantic -Wunreachable-code -Wunused-result -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1