[Mingw-cross-env-list] Customizing CFLAGS

[René Berber]

Hi,

This is just a quick question, not a problem with mingw-cross just
something I been thinking about.

Objective: Use the new (in gcc 6.x) -flto option (lto = Link time
optimization).

Reason: Since MinGW-Cross is used mainly with static libraries that
option seems worth exploring.

Antecedents: I know MinGW-Cross' Makefile disables whatever CFLAGS has
defined in the environment.

So the options are to define it globally inside MinGW-Cross' Makefile,
or define it inside each .mk file, or at least the ones that look like
good candidates for this kind of optimization (libcurl, any other big
library).

I've been using it in a project built with MinGW-Cross, just the
project, not with the libraries (in this case: libcurl, libevent,
openssl's libraries, Qt).  No problems so far.  No measurement made of
any effect either (i.e. I don't know if something changed or I'm just
wasting my time).

Oh BTW -flto doesn't work with g++, it should but it doesn't (creates a
big mess that is not easy to fix).  So this leaves the biggest libraries
I use: Qt, out of the picture; at least for now.
-- 
René Berber