[libpng17] Revised scripts/dfn.awk to work with the buggy MSYS awk that

has trouble with CRLF line endings.

scripts/dfn.awk

@@ -31,11 +31,11 @@ NR==1 && out == "/dev/null" {
 
 # Output can be sorted; two lines are recognized
 $1 == "PNG_DFN_START_SORT"{
-   sort=$2
+   sort=0+$2
    next
 }
 
-$1 == "PNG_DFN_END_SORT"{
+$1 ~ /^PNG_DFN_END_SORT/{
    # Do a very simple, slow, sort; notice that blank lines won't be
    # output by this
    for (entry in array) {
@@ -112,6 +112,9 @@ $1 == "PNG_DFN_END_SORT"{
     # editorial consistency
     sub(/ *$/, "")
 
+    # Remove trailing CR
+    sub (/
+$/, "")
 
     if (sort)
        array[$(sort)] = $0