PyFile_WriteString():  change prototype so that the string arg is
const char* instead of char*.  The change is conceptually correct, and
indirectly fixes a compiler wng introduced when somebody else innocently
passed a const char* to this function.
diff --git a/Include/fileobject.h b/Include/fileobject.h
index 94d3591..632c436 100644
--- a/Include/fileobject.h
+++ b/Include/fileobject.h
@@ -21,7 +21,7 @@
 extern DL_IMPORT(PyObject *) PyFile_GetLine(PyObject *, int);
 extern DL_IMPORT(int) PyFile_WriteObject(PyObject *, PyObject *, int);
 extern DL_IMPORT(int) PyFile_SoftSpace(PyObject *, int);
-extern DL_IMPORT(int) PyFile_WriteString(char *, PyObject *);
+extern DL_IMPORT(int) PyFile_WriteString(const char *, PyObject *);
 extern DL_IMPORT(int) PyObject_AsFileDescriptor(PyObject *);
 
 /* The default encoding used by the platform file system APIs