diff --git a/pngpread.c b/pngpread.c
index 7adb7b85..239c04d8 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -70,7 +70,7 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
          break;
       }
 
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
       case PNG_READ_tEXt_MODE:
       {
          png_push_read_tEXt(png_ptr, info_ptr);
@@ -78,7 +78,7 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
       }
 
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
       case PNG_READ_zTXt_MODE:
       {
          png_push_read_zTXt(png_ptr, info_ptr);
@@ -86,7 +86,7 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
       }
 
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
       case PNG_READ_iTXt_MODE:
       {
          png_push_read_iTXt(png_ptr, info_ptr);
@@ -154,58 +154,59 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       PNG_CONST PNG_IDAT;
       PNG_CONST PNG_IEND;
       PNG_CONST PNG_PLTE;
-#if defined(PNG_READ_bKGD_SUPPORTED)
+#ifdef PNG_READ_bKGD_SUPPORTED
       PNG_CONST PNG_bKGD;
 #endif
-#if defined(PNG_READ_cHRM_SUPPORTED)
+#ifdef PNG_READ_cHRM_SUPPORTED
       PNG_CONST PNG_cHRM;
 #endif
-#if defined(PNG_READ_gAMA_SUPPORTED)
+#ifdef PNG_READ_gAMA_SUPPORTED
       PNG_CONST PNG_gAMA;
 #endif
-#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_READ_hIST_SUPPORTED
       PNG_CONST PNG_hIST;
 #endif
-#if defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_iCCP_SUPPORTED
       PNG_CONST PNG_iCCP;
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
       PNG_CONST PNG_iTXt;
 #endif
-#if defined(PNG_READ_oFFs_SUPPORTED)
+#ifdef PNG_READ_oFFs_SUPPORTED
       PNG_CONST PNG_oFFs;
 #endif
-#if defined(PNG_READ_pCAL_SUPPORTED)
+#ifdef PNG_READ_pCAL_SUPPORTED
       PNG_CONST PNG_pCAL;
 #endif
-#if defined(PNG_READ_pHYs_SUPPORTED)
+#ifdef PNG_READ_pHYs_SUPPORTED
       PNG_CONST PNG_pHYs;
 #endif
-#if defined(PNG_READ_sBIT_SUPPORTED)
+#ifdef PNG_READ_sBIT_SUPPORTED
       PNG_CONST PNG_sBIT;
 #endif
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_READ_sCAL_SUPPORTED
       PNG_CONST PNG_sCAL;
 #endif
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
       PNG_CONST PNG_sRGB;
 #endif
-#if defined(PNG_READ_sPLT_SUPPORTED)
+#ifdef PNG_READ_sPLT_SUPPORTED
       PNG_CONST PNG_sPLT;
 #endif
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
       PNG_CONST PNG_tEXt;
 #endif
-#if defined(PNG_READ_tIME_SUPPORTED)
+#ifdef PNG_READ_tIME_SUPPORTED
       PNG_CONST PNG_tIME;
 #endif
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
       PNG_CONST PNG_tRNS;
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
       PNG_CONST PNG_zTXt;
 #endif
 #endif /* PNG_USE_LOCAL_ARRAYS */
+
    /* First we make sure we have enough data for the 4 byte chunk name
     * and the 4 byte chunk length before proceeding with decoding the
     * chunk data.  To fully decode each of these chunks, we also make
@@ -334,7 +335,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       return;
    }
 
-#if defined(PNG_READ_gAMA_SUPPORTED)
+#ifdef PNG_READ_gAMA_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -347,7 +348,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_sBIT_SUPPORTED)
+#ifdef PNG_READ_sBIT_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -360,7 +361,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_cHRM_SUPPORTED)
+#ifdef PNG_READ_cHRM_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -373,7 +374,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -386,7 +387,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_iCCP_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -399,7 +400,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_sPLT_SUPPORTED)
+#ifdef PNG_READ_sPLT_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -412,7 +413,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -425,7 +426,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_bKGD_SUPPORTED)
+#ifdef PNG_READ_bKGD_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -438,7 +439,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_READ_hIST_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -451,7 +452,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_pHYs_SUPPORTED)
+#ifdef PNG_READ_pHYs_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -464,7 +465,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_oFFs_SUPPORTED)
+#ifdef PNG_READ_oFFs_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -477,7 +478,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 #endif
 
-#if defined(PNG_READ_pCAL_SUPPORTED)
+#ifdef PNG_READ_pCAL_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -490,7 +491,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_READ_sCAL_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -503,7 +504,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_tIME_SUPPORTED)
+#ifdef PNG_READ_tIME_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -516,7 +517,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -529,7 +530,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -542,7 +543,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    }
 
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -859,7 +860,7 @@ png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
       if (!(png_ptr->zstream.avail_out))
       {
          if ((
-#if defined(PNG_READ_INTERLACING_SUPPORTED)
+#ifdef PNG_READ_INTERLACING_SUPPORTED
              png_ptr->interlaced && png_ptr->pass > 6) ||
              (!png_ptr->interlaced &&
 #endif
@@ -902,7 +903,7 @@ png_push_process_row(png_structp png_ptr)
    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
       png_do_read_transformations(png_ptr);
 
-#if defined(PNG_READ_INTERLACING_SUPPORTED)
+#ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Blow up interlaced rows to full size */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
@@ -1114,7 +1115,7 @@ png_read_push_finish_row(png_structp png_ptr)
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
 
-#if defined(PNG_READ_INTERLACING_SUPPORTED)
+#ifdef PNG_READ_INTERLACING_SUPPORTED
    if (png_ptr->interlaced)
    {
       png_ptr->row_number = 0;
@@ -1155,7 +1156,7 @@ png_read_push_finish_row(png_structp png_ptr)
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
 }
 
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
    length)
@@ -1218,7 +1219,7 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 
       png_push_crc_finish(png_ptr);
 
-#if defined(PNG_MAX_MALLOC_64K)
+#ifdef PNG_MAX_MALLOC_64K
       if (png_ptr->skip_length)
          return;
 #endif
@@ -1253,7 +1254,7 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 }
 #endif
 
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
    length)
@@ -1454,7 +1455,7 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 }
 #endif
 
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
    length)
@@ -1521,7 +1522,7 @@ png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
 
       png_push_crc_finish(png_ptr);
 
-#if defined(PNG_MAX_MALLOC_64K)
+#ifdef PNG_MAX_MALLOC_64K
       if (png_ptr->skip_length)
          return;
 #endif
@@ -1587,10 +1588,10 @@ png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
 
    if (!(png_ptr->chunk_name[0] & 0x20))
    {
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
       if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
          PNG_HANDLE_CHUNK_ALWAYS
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
          && png_ptr->read_user_chunk_fn == NULL
 #endif
          )
@@ -1600,7 +1601,7 @@ png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
       info_ptr = info_ptr; /* To quiet some compiler warnings */
    }
 
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
    if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
    {
 #ifdef PNG_MAX_MALLOC_64K
@@ -1629,7 +1630,7 @@ png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
          png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
       }
 
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
       if (png_ptr->read_user_chunk_fn != NULL)
       {
          /* Callback to user unknown chunk handler */
@@ -1694,6 +1695,7 @@ png_progressive_combine_row (png_structp png_ptr,
    PNG_CONST int FARDATA png_pass_dsp_mask[7] =
       {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
 #endif
+
    if (png_ptr == NULL)
       return;
 
diff --git a/pngrtran.c b/pngrtran.c
index 1f000dab..d173a02b 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -745,7 +745,7 @@ void /* PRIVATE */
 png_init_read_transformations(png_structp png_ptr)
 {
    png_debug(1, "in png_init_read_transformations");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (png_ptr != NULL)
 #endif
   {
@@ -1550,7 +1550,7 @@ void /* PRIVATE */
 png_do_unpack(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_unpack");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
 #else
    if (row_info->bit_depth < 8)
@@ -1643,7 +1643,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 {
    png_debug(1, "in png_do_unshift");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL && sig_bits != NULL &&
 #endif
        row_info->color_type != PNG_COLOR_TYPE_PALETTE)
@@ -1751,7 +1751,7 @@ void /* PRIVATE */
 png_do_chop(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_chop");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
 #else
    if (row_info->bit_depth == 16)
@@ -1808,7 +1808,7 @@ void /* PRIVATE */
 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_read_swap_alpha");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL)
 #endif
    {
@@ -1900,7 +1900,7 @@ void /* PRIVATE */
 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_read_invert_alpha");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL)
 #endif
    {
@@ -2007,7 +2007,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 
    png_debug(1, "in png_do_read_filler");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL  && row_info != NULL &&
 #endif
        row_info->color_type == PNG_COLOR_TYPE_GRAY)
@@ -2179,7 +2179,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 
    png_debug(1, "in png_do_gray_to_rgb");
    if (row_info->bit_depth >= 8 &&
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
@@ -2285,7 +2285,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
 
    png_debug(1, "in png_do_rgb_to_gray");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
       (row_info->color_type & PNG_COLOR_MASK_COLOR))
@@ -2766,7 +2766,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
 
    png_debug(1, "in png_do_background");
    if (background != NULL &&
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
       (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
@@ -3455,7 +3455,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
 
    png_debug(1, "in png_do_gamma");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
        ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
@@ -3643,7 +3643,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
 
    png_debug(1, "in png_do_expand_palette");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
        row_info->color_type == PNG_COLOR_TYPE_PALETTE)
@@ -3788,7 +3788,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
    png_uint_32 row_width=row_info->width;
 
    png_debug(1, "in png_do_expand");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL)
 #endif
    {
@@ -3999,7 +3999,7 @@ png_do_dither(png_row_infop row_info, png_bytep row,
    png_uint_32 row_width=row_info->width;
 
    png_debug(1, "in png_do_dither");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
    if (row != NULL && row_info != NULL)
 #endif
    {
@@ -4321,7 +4321,7 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_read_intrapixel");
    if (
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
+#ifdef PNG_USELESS_TESTS_SUPPORTED
        row != NULL && row_info != NULL &&
 #endif
        (row_info->color_type & PNG_COLOR_MASK_COLOR))