improve how the C locale is set

In conjunction with changes made to "the other repo",
we now set:

export LANG="C"
export LC_CTYPE="C"
export LC_NUMERIC="C"
export LC_TIME="C"
export LC_COLLATE="C"
export LC_MONETARY="C"
export LC_MESSAGES="C"
export LC_PAPER="C"
export LC_NAME="C"
export LC_ADDRESS="C"
export LC_TELEPHONE="C"
export LC_MEASUREMENT="C"
export LC_IDENTIFICATION="C"
export LC_ALL="C"

instead of just "$LC_ALL", "$LANG", "$LC_NUMERIC".

bin/format-headers.sh

@@ -26,9 +26,20 @@
 
 # IOCCC requires use of C locale
 #
-export LC_ALL="C"
 export LANG="C"
+export LC_CTYPE="C"
 export LC_NUMERIC="C"
+export LC_TIME="C"
+export LC_COLLATE="C"
+export LC_MONETARY="C"
+export LC_MESSAGES="C"
+export LC_PAPER="C"
+export LC_NAME="C"
+export LC_ADDRESS="C"
+export LC_TELEPHONE="C"
+export LC_MEASUREMENT="C"
+export LC_IDENTIFICATION="C"
+export LC_ALL="C"
 
 
 # modify well known markdown headers that are not in canonical form