Update the programming style of yet more scripts.

scripts/canonical_grade.in

@@ -21,7 +21,7 @@
 
 usage="Usage: canonical_grade --grade <actual>"
 
-while :
+while true
 do
     case "$1" in
     # include the file `parse_grade_options.sh-subr'
@@ -38,9 +38,9 @@ do
     shift
 done
 
-if test $# -ne 0
+if test "$#" -ne 0
 then
-    echo "$usage"
+    echo "${usage}"
     exit 1
 fi
 
@@ -50,5 +50,5 @@ fi
 # include the file `canonical_grade.sh-subr'
 @CANONICAL_GRADE@
 
-echo $GRADE
+echo ${GRADE}
 exit 0

scripts/mdprof.in

@@ -20,7 +20,7 @@
 
 prefix=@prefix@
 exec_prefix=@exec_prefix@
-PATH=@bindir@:$PATH
+PATH=@bindir@:${PATH}
 export PATH
 
 # Use less heap at the expense of increased time spent in the GC.
@@ -28,7 +28,7 @@ export PATH
 if false
 then
     MERCURY_OPTIONS_mdprof_cgi="--boehm-gc-free-space-divisor 10 \
-	${MERCURY_OPTIONS_mdprof_cgi}"
+        ${MERCURY_OPTIONS_mdprof_cgi}"
     export MERCURY_OPTIONS_mdprof_cgi
 fi
 

scripts/mkfifo_using_mknod.in

@@ -16,9 +16,9 @@
 # ENVIRONMENT VARIABLES: MERCURY_MKNOD
 
 MKNOD=${MERCURY_MKNOD=@MKNOD@}
-if test $# -ne 1
+if test "$#" -ne 1
 then
 	echo "Usage: `basename $0` filename" 1>&2
 	exit 1
 fi
-exec $MKNOD "$1" p
+exec ${MKNOD} "$1" p

scripts/mprof.in

@@ -19,7 +19,11 @@ prefix=@prefix@
 exec_prefix=@exec_prefix@
 MPROF=${MERCURY_PROFILER="@bindir@/mercury_profile"}
 
-case $# in
-    0) exec $MPROF ;;
-    *) exec $MPROF "$@" ;;
+case "$#" in
+    0)
+        exec ${MPROF}
+        ;;
+    *)
+        exec ${MPROF} "$@"
+        ;;
 esac