Re: [PATCH] perf: Drop -lstdc++ from OPENCSDLIBS

["Uwe Kleine-König" <uwe@kleine-koenig.org>]

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Hello,

I picked the wrong script so the sender address was wrong. I assume I'll 
have to fix that. Will pay more attention for v2.

On 12/2/21 14:43, Uwe Kleine-König wrote:
> From: Uwe Kleine-König <uwe@kleine-koenig.org>
> 
> When cross compiling on amd64 for arm64 the build failed on my machine with:
> 
> 	Makefile.config:493: *** Error: No libopencsd library found or the version is not up-to-date. Please install recent libopencsd to build with CORESIGHT=1.  Stop.
> 
> even though libopencsd was installed (for both amd64 and arm64). After
> some digging around I found the relevant error message in
> tools/perf/feature/test-libopencsd.make.output:
> 
> 	/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: cannot find -lstdc++
> 
> Instead of fixing the error message to also include a request to install
> libstdc++, just drop -lstdc++. With this change the build completed.
> 
> Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
> ---
> Hello,
> 
> not sure this is a pure cross compilation problem. I think in general
> it's a bad idea to link against libstdc++ explicitly. Still more if
> there is no C++ involved.

In the meantime I was pointed to 573cf5c9a152 ("perf build: Add missing 
-lstdc++ when linking with libopencsd"), and I wonder what I'm missing. 
Maybe my patch breaks the build if libopencsd is only available as .a?

I added the people involved in that commit to Cc: and look forward to 
details. The motivation to add -lstdc++ seems to be "It does not hurt" 
which is a bit weak.

Best regards
Uwe

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