add a cinelerra error which can be used to forward standard C errors from errno

src/lib/error.c

@@ -21,6 +21,14 @@
 
 #include <pthread.h>
 
+#include "lib/error.h"
+
+/*
+  predefined errors
+*/
+CINELERRA_ERROR_DEFINE (ERRNO, "errno");
+
+
 /* Thread local storage */
 static pthread_key_t cinelerra_error_tls;
 static pthread_once_t cinelerra_error_initialized = PTHREAD_ONCE_INIT;

src/lib/error.h

@@ -84,6 +84,11 @@ cinelerra_error_set (const char * err);
 const char*
 cinelerra_error ();
 
+/*
+  predefined errors
+*/
+CINELERRA_ERROR_DECLARE (ERRNO);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif