Code: emit_string(const char *str, FILE *out)
 /* Print a string with spaces replaced by '_' and non-printing characters by
    * an octal escape.
    */
{
 for (; *str; ++str)
 if (isgraph(UCHAR_MAX & *str))
         putc(*str, out);

 
       else if (isspace(UCHAR_MAX & *str))
          putc('_', out);
       else
          fprintf(out, "\\%.3o", *str);
 }

Vulnerability Type: +Priv 
CWE ID: 
Summary: Unspecified vulnerability in libpng before 1.6.20, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01, allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 23265085.
Commit Message: DO NOT MERGE Update libpng to 1.6.20

BUG:23265085
Change-Id: I85199805636d771f3597b691b63bc0bf46084833
(cherry picked from commit bbe98b40cda082024b669fa508931042eed18f82)
