update libpng

update libpng, the repo now requires a vcpkg setup for integrating but skipping the install step should allow it to work for windows an linux, mac might need more

Engine/lib/lpng/scripts/dfn.awk

@@ -1,8 +1,7 @@
 #!/bin/awk -f
+
 # scripts/dfn.awk - process a .dfn file
 #
-# last changed in libpng version 1.5.19 - August 21, 2014
-#
 # Copyright (c) 2013-2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
@@ -76,12 +75,12 @@ $1 ~ /^PNG_DFN_END_SORT/{
    if (lineno == "") lineno=NR
 
    if (sub(/^[^"]*PNG_DFN *"/,"",line) != 1) {
-	print "line", lineno ": processing failed:"
-	print orig
-	err=1
-       next
+      print "line", lineno ": processing failed:"
+      print orig
+      err=1
+      next
    } else {
-	++out_count
+      ++out_count
    }
 
    # Now examine quotes within the value:
@@ -95,7 +94,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
    #   #define first_name John
    #   #define last_name Smith
    #
-   #	PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
+   #   PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
    #
    # Might get C preprocessed to:
    #
@@ -103,7 +102,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
    #
    # Which this script reduces to:
    #
-   #	#define name "John Smith"
+   #   #define name "John Smith"
    #
    while (1) {
       # While there is an @" remove it and the next "@
@@ -125,7 +124,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
          # There is no matching "@.  Assume a split line
          else while (1) {
             if (getline nextline) {
-               # If the line starts with '#' it is a preprocesor line directive
+               # If the line starts with '#' it is a preprocessor line directive
                # from cc -E; skip it:
                if (nextline !~ /^#/) {
                   line = line " " nextline
@@ -196,7 +195,7 @@ $1 ~ /^PNG_DFN_END_SORT/{
 
 END{
    if (out_count > 0 || err > 0)
-	exit err
+      exit err
 
    print "no definition lines found"
    exit 1