exiv2 0.27.3 fails to build on PPC

[pkubaj]

Describe the bug
Building using GCC 10 on PPC/PPC64 fails with:
cc1plus: error: '-fcf-protection=full' is not supported for this target

To Reproduce
Steps to reproduce the behaviour:

1. Try building on PPC platforms.

Expected behavior
exiv2 should build.

Desktop (please complete the following information):

• OS: FreeBSD
• Compiler & Version GCC 10.1
• Compilation mode and/or compiler flags
  Default flags.

Additional context
1ea63cc fixed build on arm, ppc needs the same.

[pkubaj]

On PPC64 CMAKE_SYSTEM_PROCESSOR apparently is "powerpc64".

[clanmills]

It never fails to amaze me that two people can report almost the same thing on the same day in code that hasn't been changed for years!

Right now I'm investigating a issue with a build flag on a very elderly Xcode 6.1. I'll apply similar medicine for -fcf-protection=full.

On which branch are you working? I maintain the 0.27-maintenance branch. Can you test my fix when it's available?

[pkubaj]

I'm not using any branch, I just build from FreeBSD ports tree.
And it's not that it got broken "years" ago. 0.27.2 built just fine, the regression happened in 0.27.3.

[clanmills]

I don't know what FreeBSD ports tree is. I frequently build and test 0.27.3 on FreeBSD on our buildserver. I don't have a PPC machine. Can you test my fix when it's available?

[pkubaj]

Well, I already wrote in my 1st message that PPC need the same that was done for ARM. So the correct fix is putting:
if (NOT (${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm" OR ${CMAKE_SYSTEM_PROCESSOR} MATCHES "powerpc")) in cmake/compilerFlags.cmake.

[clanmills]

I don't know anything about that "arm" code on master. I deal with the 0.27-maintenance branch.

[pkubaj]

Then this commit adding ARM should be merged to 0.27-maintenance. It should also add PPC (and other broken architectures, if there are any).

Anyway, I think -fcf-protection is supported only on x86_64, so it should only be enabled there (but that should be researched first).

[clanmills]

I've unassigned myself from this and will leave this to the people managing 'master'.

[jtojnar]

With #1252 merged, this is likely fixed on master but still an issue in 0.27 branch.

[clanmills]

I agree that this is an issue on the 0.27-maintenance branch. I tried to fix this in July. My dyslexia got the better of me. #1245

@ryandesign offered to help. I would very much appreciate some help with both the necessary changes (to support ARM, PPC and Xcode 6.1) and to test the builds. I've set up a VM for Xcode 6.1. Should I buy a raspberry pi? Any suggestions?

[jtojnar]

I opened #1271 fixing this for 0.27.

[clanmills]

I believe #1271 solves this issue. Thanks to @jtojnar for this contribution. I'm going to close this.