[Ltrace-devel] [PATCH] output.c: Fix open_memstream() compilation error

[Sedat Dilek]

With the latest ltrace from GIT repository my build on MIPSEL breaks with
the following error messages:

[ build.log ]
...
output.c: In function 'delim_output':
output.c:626:3: error: implicit declaration of function 'open_memstream' [-Werror=implicit-function-declaration]
output.c:626:15: error: initialization makes pointer from integer without a cast [-Werror]
cc1: all warnings being treated as errors
make[3]: *** [output.lo] Error 1

My self-compiled MIPSEL toolchain consists of gcc-4.7.2-RC and uClibc-0.9.33.2
and I have set in my uClibc dot-config file:

     UCLIBC_HAS_GLIBC_CUSTOM_STREAMS=y

...which allows the usage of open_memstream().

While digging deeper into the problem I have found a thread on uClibc-ML [1]
called "stdio.h and open_memstream()".
There people recommended to set "-D_GNU_SOURCE" to the compiler flags and
the reporter confirmed this worked for him.

First, I tried to set this flag globally in my ltrace Makefile, but this
leads to more errors like "...D_GNU_SOURCE redefined..." as some other
c-files like "proc.c" have this define already.

Thus add a separate define to "output.c" file.
This fixes the issue for me.

Tested against ltrace-git (commit 5511311: "Drop two non-bugs from ltrace.1")

[1] http://lists.uclibc.org/pipermail/uclibc/2012-January/046279.html

Signed-off-by: Sedat Dilek <sedat.dilek at gmail.com>
---
 output.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/output.c b/output.c
index 94c433d..1555f2f 100644
--- a/output.c
+++ b/output.c
@@ -24,6 +24,7 @@
 
 #include "config.h"
 
+#define _GNU_SOURCE /* For open_memstream.  */
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
-- 
1.7.9.5