Issue #13088: Add shared Py_hexdigits constant to format a number into base 16
diff --git a/Modules/_hashopenssl.c b/Modules/_hashopenssl.c
index dd4317f..d37689e 100644
--- a/Modules/_hashopenssl.c
+++ b/Modules/_hashopenssl.c
@@ -201,13 +201,11 @@
 
     /* Make hex version of the digest */
     for(i=j=0; i<digest_size; i++) {
-        char c;
+        unsigned char c;
         c = (digest[i] >> 4) & 0xf;
-        c = (c>9) ? c+'a'-10 : c + '0';
-        hex_digest[j++] = c;
+        hex_digest[j++] = Py_hexdigits[c];
         c = (digest[i] & 0xf);
-        c = (c>9) ? c+'a'-10 : c + '0';
-        hex_digest[j++] = c;
+        hex_digest[j++] = Py_hexdigits[c];
     }
     retval = PyUnicode_FromStringAndSize(hex_digest, digest_size * 2);
     PyMem_Free(hex_digest);