Add -fno-lto for GCC and compatibles

[Jeffrey Walton]

Hi Everyone,

LTO is slowly accumulating bugs. From what I have seen in the
post-mortems, it looks like LTO is either (1) results in a compile
error (older compilers) or (2) results in a runtime error (newer
compilers).

For (2), it appears LTO mishandles code with GCC extended inline
assembly. To build the library with LTO, you have to use
-DCRYPTOPP_DISABLE_ASM. That gets us past the self tests but causes a
slowdown in the library.

Worse, most users and distros are not aware of the LTO problems so the
library gets built with it but without -DCRYPTOPP_DISABLE_ASM.

I think we should add -fno-lto when GCC and compatibles support it.

What do you think?

Jeff

[Uri Blumenthal]

I don't see a good alternative. -fno-lto seems it.

> On May 5, 2021, at 14:23, Jeffrey Walton <nolo...@gmail.com> wrote:
>
> Hi Everyone,

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