Misc fixes for compilation with current SDCC compiler

include/nuttx/compiler.h

@@ -200,6 +200,7 @@
 #  define CONFIG_HAVE_FARPOINTER 1
 
 #elif defined(__mc68hc1x__)
+
 /* No I-space access qualifiers */
 
 #  define IOBJ
@@ -269,10 +270,19 @@
 
 #  define CONFIG_CAN_PASS_STRUCTS 1
 
+/* Indicate that a local variable is not used */
+
+#  define UNUSED(a) ((void)(a))
+
 /* SDCC-specific definitions ************************************************/
 
 #elif defined(SDCC)
 
+/* No I-space access qualifiers */
+
+#  define IOBJ
+#  define IPTR
+
 /* Pre-processor */
 
 #  define CONFIG_CPP_HAVE_VARARGS 1 /* Supports variable argument macros */
@@ -329,6 +339,10 @@
 
 #  define reentrant_function __reentrant
 
+/* Indicate that a local variable is not used */
+
+#  define UNUSED(a) ((void)(a))
+
 /* It is assumed that the system is build using the small
  * data model with storage defaulting to internal RAM.
  * The NEAR storage class can also be used to address data
@@ -386,6 +400,10 @@
 
 #  undef  CONFIG_CAN_PASS_STRUCTS
 
+/* Indicate that a local variable is not used */
+
+#  define UNUSED(a) ((void)(a))
+
 /* Zilog-specific definitions ***********************************************/
 
 #elif defined(__ZILOG__)
@@ -505,6 +523,10 @@
 
 #  define CONFIG_CAN_PASS_STRUCTS 1
 
+/* Indicate that a local variable is not used */
+
+#  define UNUSED(a) ((void)(a))
+
 /* ICCARM-specific definitions ***********************************************/
 
 #elif defined(__ICCARM__)
@@ -533,6 +555,7 @@
 #  define NEAR
 #  define DSEG
 #  define CODE
+#  define IOBJ
 #  define IPTR
 
 #  define __asm__       asm
@@ -588,6 +611,8 @@
 #  undef  CONFIG_HAVE_LONG_DOUBLE
 #  undef  CONFIG_CAN_PASS_STRUCTS
 
+#  define UNUSED(a) ((void)(a))
+
 #endif
 
 /****************************************************************************

include/nuttx/fs/fs.h

@@ -644,14 +644,6 @@ int file_dup2(FAR struct file *filep1, FAR struct file *filep2);
 int fs_dupfd(int fd, int minfd);
 #endif
 
-/****************************************************************************
- * Name: file_dup
- *
- * Description:
- *   Equivalent to the non-standard fs_dupfd() function except that it
- *   accepts a struct file instance instead of a file descriptor.  Currently
- *   used only by file_vfcntl();
- *
 /****************************************************************************
  * Name: file_dup
  *