From: bors <bors@rust-lang.org>
Date: Wed, 21 May 2014 02:16:15 +0000 (-0700)
Subject: auto merge of #13823 : pnkfelix/rust/fsk-fix-13805, r=alexcrichton
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=f30382d624d4a523262df05234b1c20b7de4ac0c;p=rust.git

auto merge of #13823 : pnkfelix/rust/fsk-fix-13805, r=alexcrichton

Make configure script respect (and save) values for `CC`, `CXX`, `CFLAGS` etc.

I mostly tried to remain backwards compatible with old invocations of
the `configure` script; if you do not want to use `CC` et al., you
should not have to; you can keep using `--enable-clang` and/or
`--enable-ccache`.

The overall intention is to capture the following precedences for
guessing the C compiler:

 1. Value of `CC` at `make` invocation time.
 2. Value of `CC` at `configure` invocation time.
 3. Compiler inferred at configure invocation time (`gcc` or `clang`).

The strategy is to check (at `configure` time) if each of the
environment variables is set, and if so, save its value in a
corresponding `CFG_` variable (e.g. `CFG_CC`).

The `configure` script also does not attempt to infer the compiler if
`CC` is set; but if `--enable-clang` was passed, then it *does* still
attempt to validate that the clang version is compatible.

Then, in the makefiles, if `CC` is not set but `CFG_CC` is, then we
use the `CFG_CC` setting as `CC`.

Fix #13805.
---

f30382d624d4a523262df05234b1c20b7de4ac0c