png: Split library to thirdparty dir and allow unbundling

Uses the new structure agreed upon in #6157, but the thirdparty/ folder
does not behave following a logic similar to that of modules/ yet.

The png driver can't be moved to a module as discussed in #6157, as it's
required by core together with a few other ImageLoader implementations
(see drivers/register_driver_types.cpp:register_core_driver_types())

Dropped the possibility to disable PNG support, it's a core component
of Godot.

1 files changed, 153 insertions, 0 deletions

diff --git a/thirdparty/libpng/pngdebug.h b/thirdparty/libpng/pngdebug.h
new file mode 100644
index 0000000000..15a7ed0c95
--- /dev/null
+++ b/thirdparty/libpng/pngdebug.h
@@ -0,0 +1,153 @@
+
+/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
+ *
+ * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Copyright (c) 1998-2002,2004,2006-2013 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Define PNG_DEBUG at compile time for debugging information.  Higher
+ * numbers for PNG_DEBUG mean more debugging information.  This has
+ * only been added since version 0.95 so it is not implemented throughout
+ * libpng yet, but more support will be added as needed.
+ *
+ * png_debug[1-2]?(level, message ,arg{0-2})
+ *   Expands to a statement (either a simple expression or a compound
+ *   do..while(0) statement) that outputs a message with parameter
+ *   substitution if PNG_DEBUG is defined to 2 or more.  If PNG_DEBUG
+ *   is undefined, 0 or 1 every png_debug expands to a simple expression
+ *   (actually ((void)0)).
+ *
+ *   level: level of detail of message, starting at 0.  A level 'n'
+ *          message is preceded by 'n' 3-space indentations (not implemented
+ *          on Microsoft compilers unless PNG_DEBUG_FILE is also
+ *          defined, to allow debug DLL compilation with no standard IO).
+ *   message: a printf(3) style text string.  A trailing '\n' is added
+ *            to the message.
+ *   arg: 0 to 2 arguments for printf(3) style substitution in message.
+ */
+#ifndef PNGDEBUG_H
+#define PNGDEBUG_H
+/* These settings control the formatting of messages in png.c and pngerror.c */
+/* Moved to pngdebug.h at 1.5.0 */
+#  ifndef PNG_LITERAL_SHARP
+#    define PNG_LITERAL_SHARP 0x23
+#  endif
+#  ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET
+#    define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b
+#  endif
+#  ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET
+#    define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d
+#  endif
+#  ifndef PNG_STRING_NEWLINE
+#    define PNG_STRING_NEWLINE "\n"
+#  endif
+
+#ifdef PNG_DEBUG
+#  if (PNG_DEBUG > 0)
+#    if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
+#      include <crtdbg.h>
+#      if (PNG_DEBUG > 1)
+#        ifndef _DEBUG
+#          define _DEBUG
+#        endif
+#        ifndef png_debug
+#          define png_debug(l,m)  _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
+#        endif
+#        ifndef png_debug1
+#          define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
+#        endif
+#        ifndef png_debug2
+#          define png_debug2(l,m,p1,p2) \
+             _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
+#        endif
+#      endif
+#    else /* PNG_DEBUG_FILE || !_MSC_VER */
+#      ifndef PNG_STDIO_SUPPORTED
+#        include <stdio.h> /* not included yet */
+#      endif
+#      ifndef PNG_DEBUG_FILE
+#        define PNG_DEBUG_FILE stderr
+#      endif /* PNG_DEBUG_FILE */
+
+#      if (PNG_DEBUG > 1)
+#        ifdef __STDC__
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : "")))); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1,p2);\
+       } while (0)
+#          endif
+#        else /* __STDC __ */
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1,p2); \
+       } while (0)
+#          endif
+#        endif /* __STDC __ */
+#      endif /* (PNG_DEBUG > 1) */
+
+#    endif /* _MSC_VER */
+#  endif /* (PNG_DEBUG > 0) */
+#endif /* PNG_DEBUG */
+#ifndef png_debug
+#  define png_debug(l, m) ((void)0)
+#endif
+#ifndef png_debug1
+#  define png_debug1(l, m, p1) ((void)0)
+#endif
+#ifndef png_debug2
+#  define png_debug2(l, m, p1, p2) ((void)0)
+#endif
+#endif /* PNGDEBUG_H */