[libpng15] De-configured build fixes to make a range of deconfiguration options

(such as switching off read or write support) work in more cases.  Also
upgraded pngtest and pngvalid to the libpng 1.6 versions (with some
modifications) which provide more extensive testing.  Replaced pngtest.png
because pngtest writes the ancillary chunks in a different order.

pngpriv.h

@@ -416,7 +416,7 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
    /* This is used because in some compiler implementations non-aligned
     * structure members are supported, so the offsetof approach below fails.
-    * Set PNG_ALIGN_TO_SIZE=0 for compiler combinations where unaligned access
+    * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
     * is good for performance.  Do not do this unless you have tested the result
     * and understand it.
     */
@@ -823,10 +823,8 @@ PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
 #  ifdef PNG_FLOATING_POINT_SUPPORTED
 PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
 #  endif
-#  ifdef PNG_FIXED_POINT_SUPPORTED
 PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
     png_fixed_point file_gamma));
-#  endif
 #endif
 
 #ifdef PNG_WRITE_sBIT_SUPPORTED
@@ -1491,14 +1489,16 @@ PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
 /* ASCII to FP interfaces, currently only implemented if sCAL
  * support is required.
  */
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_sCAL_SUPPORTED
 /* MAX_DIGITS is actually the maximum number of characters in an sCAL
  * width or height, derived from the precision (number of significant
  * digits - a build time settable option) and assumpitions about the
  * maximum ridiculous exponent.
  */
 #define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
+#endif
 
+#ifdef PNG_sCAL_SUPPORTED
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 PNG_EXTERN void png_ascii_from_fp PNGARG((png_structp png_ptr, png_charp ascii,
     png_size_t size, double fp, unsigned int precision));
@@ -1629,7 +1629,7 @@ PNG_EXTERN png_fixed_point png_muldiv_warn PNGARG((png_structp png_ptr,
     png_fixed_point a, png_int_32 multiplied_by, png_int_32 divided_by));
 #endif
 
-#ifdef PNG_READ_GAMMA_SUPPORTED
+#if (defined PNG_READ_GAMMA_SUPPORTED) || (defined PNG_cHRM_SUPPORTED)
 /* Calculate a reciprocal - used for gamma values.  This returns
  * 0 if the argument is 0 in order to maintain an undefined value,
  * there are no warnings.
@@ -1664,6 +1664,62 @@ PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr,
     int bit_depth));
 #endif
 
+/* Missing declarations if FIXED_POINT is *not* supported - fixed properly
+ * in libpng 1.6
+ */
+#ifndef PNG_FIXED_POINT_SUPPORTED
+#ifdef PNG_cHRM_SUPPORTED
+PNG_EXTERN png_uint_32 png_get_cHRM_XYZ_fixed PNGARG(
+    (png_structp png_ptr, png_const_infop info_ptr,
+    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+    png_fixed_point *int_blue_Z));
+PNG_EXTERN void png_set_cHRM_XYZ_fixed PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
+    png_fixed_point int_red_Z, png_fixed_point int_green_X,
+    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+    png_fixed_point int_blue_Z));
+PNG_EXTERN void png_set_cHRM_fixed PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_fixed_point int_white_x,
+    png_fixed_point int_white_y, png_fixed_point int_red_x,
+    png_fixed_point int_red_y, png_fixed_point int_green_x,
+    png_fixed_point int_green_y, png_fixed_point int_blue_x,
+    png_fixed_point int_blue_y));
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_EXTERN png_uint_32 png_get_gAMA_fixed PNGARG(
+    (png_const_structp png_ptr, png_const_infop info_ptr,
+    png_fixed_point *int_file_gamma));
+PNG_EXTERN void png_set_gAMA_fixed PNGARG((png_structp png_ptr,
+    png_infop info_ptr, png_fixed_point int_file_gamma));
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+PNG_EXTERN void png_set_background_fixed PNGARG((png_structp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, png_fixed_point background_gamma));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+PNG_EXTERN void png_set_alpha_mode_fixed PNGARG((png_structp png_ptr,
+    int mode, png_fixed_point output_gamma));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+PNG_EXTERN void png_set_gamma_fixed PNGARG((png_structp png_ptr,
+    png_fixed_point screen_gamma, png_fixed_point override_file_gamma));
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+PNG_EXTERN void png_set_rgb_to_gray_fixed PNGARG((png_structp png_ptr,
+    int error_action, png_fixed_point red, png_fixed_point green));
+#endif
+#endif /* FIX MISSING !FIXED_POINT DECLARATIONS */
+
 #ifdef PNG_FILTER_OPTIMIZATIONS
 PNG_EXTERN void PNG_FILTER_OPTIMIZATIONS(png_structp png_ptr, unsigned int bpp);
    /* This is the initialization function for hardware specific optimizations,