From 94e1911ca24726b7cb3efe2f8b9eb7a784757e18 Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyfox@gentoo.org>
Date: Sun, 26 Jan 2020 18:35:13 +0000
Subject: [PATCH] squashfs-tools: fix build failure against gcc-10
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On gcc-10 (and gcc-9 -fno-common) build fails as:

```
cc ... -o mksquashfs
ld: read_fs.o:(.bss+0x0):
  multiple definition of `fwriter_buffer'; mksquashfs.o:(.bss+0x400c90): first defined here
ld: read_fs.o:(.bss+0x8):
  multiple definition of `bwriter_buffer'; mksquashfs.o:(.bss+0x400c98): first defined here
```

gcc-10 will change the default from -fcommon to fno-common:
https://gcc.gnu.org/PR85678.

The error also happens if CFLAGS=-fno-common passed explicitly.

Reported-by: Toralf Förster
Bug: https://bugs.gentoo.org/706456
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Jacob Kroon <jacob.kroon@gmail.com>
Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/fe2f5da4b0f8994169c53e84b7cb8a0feefc97b5]
---
 squashfs-tools/mksquashfs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/squashfs-tools/mksquashfs.h b/squashfs-tools/mksquashfs.h
index 1beefef..b650306 100644
--- a/squashfs-tools/mksquashfs.h
+++ b/squashfs-tools/mksquashfs.h
@@ -143,7 +143,7 @@ struct append_file {
 #endif
 
 extern struct cache *reader_buffer, *fragment_buffer, *reserve_cache;
-struct cache *bwriter_buffer, *fwriter_buffer;
+extern struct cache *bwriter_buffer, *fwriter_buffer;
 extern struct queue *to_reader, *to_deflate, *to_writer, *from_writer,
 	*to_frag, *locked_fragment, *to_process_frag;
 extern struct append_file **file_mapping;