Update libpng to 1.2.38 to patch a minor security issue.
diff --git a/pngerror.c b/pngerror.c
index 7652171..d68416b 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,12 +1,15 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.2.34 [December 18, 2008]
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Last changed in libpng 1.2.37 [June 4, 2009]
+ * Copyright (c) 1998-2009 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
+ *
  * This file provides a location for all error handling.  Users who
  * need special error handling are expected to write replacement functions
  * and use png_set_error_fn() to use those functions.  See the instructions
@@ -44,7 +47,7 @@
      {
        if (*error_message == '#')
        {
-         /* Strip "#nnnn " from beginning of error message. */
+           /* Strip "#nnnn " from beginning of error message. */
            int offset;
            for (offset = 1; offset<15; offset++)
               if (error_message[offset] == ' ')
@@ -217,7 +220,7 @@
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
    if (*error_message == '#')
    {
-     /* Strip "#nnnn " from beginning of warning message. */
+     /* Strip "#nnnn " from beginning of error message. */
      int offset;
      char error_number[16];
      for (offset = 0; offset<15; offset++)
@@ -229,15 +232,23 @@
      if ((offset > 1) && (offset < 15))
      {
        error_number[offset - 1] = '\0';
-       fprintf(stderr, "libpng error no. %s: %s\n", error_number,
-          error_message + offset + 1);
+       fprintf(stderr, "libpng error no. %s: %s",
+          error_number, error_message + offset + 1);
+       fprintf(stderr, PNG_STRING_NEWLINE);
      }
      else
-       fprintf(stderr, "libpng error: %s, offset=%d\n", error_message, offset);
+     {
+       fprintf(stderr, "libpng error: %s, offset=%d",
+          error_message, offset);
+       fprintf(stderr, PNG_STRING_NEWLINE);
+     }
    }
    else
 #endif
-   fprintf(stderr, "libpng error: %s\n", error_message);
+   {
+      fprintf(stderr, "libpng error: %s", error_message);
+      fprintf(stderr, PNG_STRING_NEWLINE);
+   }
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
@@ -257,7 +268,7 @@
    PNG_ABORT();
 #endif
 #ifdef PNG_NO_CONSOLE_IO
-   error_message = error_message; /* make compiler happy */
+   error_message = error_message; /* Make compiler happy */
 #endif
 }
 
@@ -285,19 +296,27 @@
      if ((offset > 1) && (offset < 15))
      {
        warning_number[offset + 1] = '\0';
-       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
-          warning_message + offset);
+       fprintf(stderr, "libpng warning no. %s: %s",
+          warning_number, warning_message + offset);
+       fprintf(stderr, PNG_STRING_NEWLINE);
      }
      else
-       fprintf(stderr, "libpng warning: %s\n", warning_message);
+     {
+       fprintf(stderr, "libpng warning: %s",
+          warning_message);
+       fprintf(stderr, PNG_STRING_NEWLINE);
+     }
    }
    else
 #  endif
-     fprintf(stderr, "libpng warning: %s\n", warning_message);
+   {
+     fprintf(stderr, "libpng warning: %s", warning_message);
+     fprintf(stderr, PNG_STRING_NEWLINE);
+   }
 #else
-   warning_message = warning_message; /* make compiler happy */
+   warning_message = warning_message; /* Make compiler happy */
 #endif
-   png_ptr = png_ptr; /* make compiler happy */
+   png_ptr = png_ptr; /* Make compiler happy */
 }
 #endif /* PNG_NO_WARNINGS */