Subject: [PATCH] qstat: fix build failure against gcc-10
From: Sergei Trofimovich <[email-masked]>
Date: Sun, 26 Jan 2020 11:15:10 +0000

On gcc-10 (and gcc-9 -fno-common) build fails as:

```
gcc ... -o qstat ...
ld: config.o:qstat/display_json.h:24:
  multiple definition of `json_printed'; xform.o:qstat/display_json.h:24: first defined here
ld: config.o:qstat/display_json.h:23:
  multiple definition of `json_encoding'; xform.o:qstat/display_json.h:23: 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/706390
Signed-off-by: Sergei Trofimovich <[email-masked]>
--- a/debug.c
+++ b/debug.c
@@ -114,6 +114,7 @@ static void _dump_packet(const char* tag, const char* buf, int buflen)
 	close(fd);
 }
 
+int do_dump = 0;
 ssize_t send_dump(int s, const void *buf, size_t len, int flags)
 {
 	if(do_dump)
--- a/debug.h
+++ b/debug.h
@@ -47,7 +47,7 @@ void dump_packet(const char* buf, int buflen);
 #endif
 #include <sys/types.h>
 #include <sys/stat.h>
-int do_dump;
+extern int do_dump;
 ssize_t send_dump(int s, const void *buf, size_t len, int flags);
 #ifndef QSTAT_DEBUG_C
 #define send(s, buf, len, flags) send_dump(s, buf, len, flags)