[master] Added macros to detect use of deprecated features.

Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
    PNG_ALLOCATED macros to detect deprecated direct access to the
    png_struct or info_struct members and other deprecated usage in
    applications (John Bowler).
  Added -DPNG_CONFIGURE_LIBPNG to the makefile CFLAGS, to prevent warnings
    about direct access to png structs by libpng functions while building
    libpng.
  Removed three direct references to read_info_ptr members in pngtest.c
    that were detected by the new PNG_DEPSTRUCT macro.
  Moved the png_debug macro definitions and the png_read_destroy(),
    png_write_destroy() and png_far_to_near() prototypes from png.h
    to pngpriv.h (John Bowler)
  Moved the synopsis lines for png_read_destroy(), png_write_destroy()
    png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.

pngpriv.h

@@ -831,6 +831,129 @@ PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
    int color_type, int interlace_type, int compression_type,
    int filter_type));
 
+/* Free all memory used by the read (old method - NOT DLL EXPORTED) */
+extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_infop end_info_ptr));
+
+/* Free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
+extern void png_write_destroy PNGARG((png_structp png_ptr));
+
+#ifdef USE_FAR_KEYWORD  /* memory model conversion function */
+extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,
+   int check));
+#endif /* USE_FAR_KEYWORD */
+
+/* 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.
+ */
+#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_DEBUG_FILE
+#define PNG_DEBUG_FILE stderr
+#endif /* PNG_DEBUG_FILE */
+
+#if (PNG_DEBUG > 1)
+/* Note: ["%s"m PNG_STRING_NEWLINE] probably does not work on
+ * non-ISO compilers
+ */
+#  ifdef __STDC__
+#    ifndef png_debug
+#      define png_debug(l,m) \
+       { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
+       }
+#    endif
+#    ifndef png_debug1
+#      define png_debug1(l,m,p1) \
+       { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
+       }
+#    endif
+#    ifndef png_debug2
+#      define png_debug2(l,m,p1,p2) \
+       { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
+       }
+#    endif
+#  else /* __STDC __ */
+#    ifndef png_debug
+#      define png_debug(l,m) \
+       { \
+       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); \
+       }
+#    endif
+#    ifndef png_debug1
+#      define png_debug1(l,m,p1) \
+       { \
+       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); \
+       }
+#    endif
+#    ifndef png_debug2
+#      define png_debug2(l,m,p1,p2) \
+       { \
+       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); \
+       }
+#    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)
+#endif
+#ifndef png_debug1
+#define png_debug1(l, m, p1)
+#endif
+#ifndef png_debug2
+#define png_debug2(l, m, p1, p2)
+#endif
+
+#if 0
+extern PNG_EXPORT(png_bytep,png_sig_bytes) PNGARG((void));
+#endif
+
 /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
 
 #ifdef __cplusplus