macOS: error: use of undeclared identifier 'CLONE_NOOWNERCOPY'

[ryandesign]

Hi, I'm the maintainer of ccache in MacPorts. After updating to 4.0 it became apparent that it doesn't build anymore on some older macOS versions like 10.12 for various reasons. 4.0 does build on 10.13 and up. 3.7.12 and earlier built fine on older macOS versions down to 10.6 or maybe even earlier.

How to reproduce

1. Compile ccache 4.0 on macOS 10.12

Actual behavior

https://build.macports.org/builders/ports-10.12_x86_64-builder/builds/129053/steps/install-port/logs/stdio

src/Util.cpp:259:44: error: use of undeclared identifier 'CLONE_NOOWNERCOPY'
  if (clonefile(src.c_str(), dest.c_str(), CLONE_NOOWNERCOPY) != 0) {
                                           ^

Expected behavior

successful compile

Environment

ccache version 4.0

macOS Sierra v10.12.6 (16G2136)
Xcode v9.2 (9C40b)
Apple LLVM version 9.0.0 (clang-900.0.39.2)

[erijo]

I pushed a potential fix for this to the same branch as my potential fix for #689.

[ryandesign]

Thanks, the fix for this issue works. I haven't tested the other fixes yet.