nuttx/fs: Remove explicity references to errno. That is a problem from within the kernel for certain configurations

fs/mmap/fs_mmap.c

@@ -136,14 +136,14 @@ FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
       (flags & (MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_DENYWRITE)) != 0)
     {
       fdbg("Unsupported options, prot=%x flags=%04x\n", prot, flags);
-      errno = ENOSYS;
+      set_errno(ENOSYS);
       return MAP_FAILED;
     }
 
   if (length == 0 || (flags & MAP_SHARED) == 0)
     {
       fdbg("Invalid options, lengt=%d flags=%04x\n", length, flags);
-      errno = EINVAL;
+      set_errno(EINVAL);
       return MAP_FAILED;
     }
 #endif
@@ -163,7 +163,7 @@ FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
 #ifdef CONFIG_FS_RAMMAP
       return rammap(fd, length, offset);
 #else
-      fdbg("ioctl(FIOC_MMAP) failed: %d\n", errno);
+      fdbg("ioctl(FIOC_MMAP) failed: %d\n", get_errno());
       return MAP_FAILED;
 #endif
     }

fs/mmap/fs_munmap.c

@@ -205,7 +205,7 @@ int munmap(FAR void *start, size_t length)
 
 errout_with_semaphore:
   sem_post(&g_rammaps.exclsem);
-  errno = err;
+  set_errno(err);
   return ERROR;
 }
 

fs/mmap/fs_rammap.h

@@ -117,7 +117,7 @@ extern struct fs_allmaps_s g_rammaps;
  *
  ****************************************************************************/
 
-extern void rammap_initialize(void);
+void rammap_initialize(void);
 
 /****************************************************************************
  * Name: rammmap
@@ -144,7 +144,7 @@ extern void rammap_initialize(void);
  *
  ****************************************************************************/
 
-extern FAR void *rammap(int fd, size_t length, off_t offset);
+FAR void *rammap(int fd, size_t length, off_t offset);
 
 #endif /* CONFIG_FS_RAMMAP */
 #endif /* __FS_MMAP_RAMMAP_H */