tree 77c61b4172fa4f09be62de0ef527b71f108228c9
parent e9b12988c0e31f9f87dcd3dd38313ea765f01a01
author Nico Weber <thakis@chromium.org> 1659788951 -0400
committer Copybara-Service <copybara-worker@google.com> 1659789450 -0700

[gn build] Try to fix build on linux after std=c++17 switch

glibc annotates `process_vm_readv` with `__THROW`.
lldb/include/lldb/Host/linux/Uio.h and
lldb/source/Host/linux/LibcGlue.cpp don't.

Having a mismatch causes an error with c++17:

    ../../lldb/source/Host/linux/LibcGlue.cpp:18:9:
        error: 'process_vm_readv' is missing exception specification 'throw()'
    ssize_t process_vm_readv(::pid_t pid, const struct iovec *local_iov,
            ^
    ../../lldb/include/lldb/Host/linux/Uio.h:18:9:
        note: previous declaration is here
    ssize_t process_vm_readv(::pid_t pid, const struct iovec *local_iov,
            ^

The diagnostic is a bit misleading, since the previous declaration
in the sysroot (in usr/include/x76_64-linux-gnu/bits/uio-ext.h) is
what has the `__THROW`.

In the cmake build, cmake sets `HAVE_PROCESS_VM_READV` correctly based
on header probing.

In the GN build, just set it to 1 unconditionally on linux. If that
turns out to not be good enough everywhere, we'll have to add a GN arg
for this.

(I'm also setting it to 1 on Android. I'm not sure if that's correct --
but we don't build lldb for Android anyways.)

GitOrigin-RevId: 547c551925c8f4dd979ba5cf16c857091a80254b