tiff: declare var at begin of block

src/encode.c

@@ -734,10 +734,11 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
         }
 
         if (PyTuple_Check(value)) {
-            is_var_length = 1;
-
             Py_ssize_t len;
             len = PyTuple_Size(value);
+
+            is_var_length = 1;
+
             if (!len) {
                 continue;
             }

src/libImaging/TiffDecode.c

@@ -525,23 +525,25 @@ int ImagingLibTiffMergeFieldInfo(ImagingCodecState state, TIFFDataType field_typ
     int status = 0;
 
     // custom fields added with ImagingLibTiffMergeFieldInfo are only used for
-    // decoding, ignore read_count;
-    int read_count = 0;
-
+    // decoding, ignore readcount;
+    int readcount = 0;
     // we support writing single value, or a variable number of values
-    int write_count = 1;
+    int writecount = 1;
+    // whether the first value should encode the number of values.
+    int passcount = 0;
+
+    TIFFFieldInfo info[] = {
+        { key, readcount, writecount, field_type, FIELD_CUSTOM, 1, passcount, field_name }
+    };
+
     if (is_var_length) {
-        write_count = -1;
+        info[0].field_writecount = -1;
     }
 
-    // whether the first value should encode the number of values.
-    int passcount = 0;
     if (is_var_length && field_type != TIFF_ASCII) {
-        passcount = 1;
+        info[0].field_passcount = 1;
     }
-    const TIFFFieldInfo info[] = {
-        { key, read_count, write_count, field_type, FIELD_CUSTOM, 1, passcount, field_name }
-    };
+
     n = sizeof(info) / sizeof(info[0]);
 
     // Test for libtiff 4.0 or later, excluding libtiff 3.9.6 and 3.9.7