Add function attributes that allow GCC to check the arguments of printf-like
functions.
diff --git a/Include/sysmodule.h b/Include/sysmodule.h
index 92f2207..ca6b6d7 100644
--- a/Include/sysmodule.h
+++ b/Include/sysmodule.h
@@ -13,8 +13,10 @@
DL_IMPORT(void) PySys_SetArgv(int, char **);
DL_IMPORT(void) PySys_SetPath(char *);
-DL_IMPORT(void) PySys_WriteStdout(const char *format, ...);
-DL_IMPORT(void) PySys_WriteStderr(const char *format, ...);
+DL_IMPORT(void) PySys_WriteStdout(const char *format, ...)
+ __attribute__((format(printf, 1, 2)));
+DL_IMPORT(void) PySys_WriteStderr(const char *format, ...)
+ __attribute__((format(printf, 1, 2)));
extern DL_IMPORT(PyObject *) _PySys_TraceFunc, *_PySys_ProfileFunc;
extern DL_IMPORT(int) _PySys_CheckInterval;