rustc-1.24.0-src: cannot find -lstdc++ on FreeBSD 11.1

[triaxx]

I am trying to build lang/rust for FreeBSD using the pkgsrc framework.

The clang++ check fails during LLVM build since ld cannot find -lstdc++. Actually -lc++ should be used.

This dirty hack solves the problem but there probably is a better way to do that:

--- src/bootstrap/native.rs.orig    2018-02-12 18:51:18.000000000 +0000
+++ src/bootstrap/native.rs
@@ -223,7 +223,11 @@ impl Step for Llvm {
 
             cfg.build_arg("-j").build_arg(build.jobs().to_string());
             cfg.define("CMAKE_C_FLAGS", build.cflags(target).join(" "));
-            cfg.define("CMAKE_CXX_FLAGS", build.cflags(target).join(" "));
+            if target.contains("freebsd") {
+                cfg.define("CMAKE_CXX_FLAGS", build.cflags(target).join(" ") + " -stdlib=libc++");
+            } else {
+                cfg.define("CMAKE_CXX_FLAGS", build.cflags(target).join(" "));
+            }   
             if let Some(ar) = build.ar(target) {
                 if ar.is_absolute() {
                     // LLVM build breaks if `CMAKE_AR` is a relative path, for some reason it

The build trace is attached in the following file:
rust.log

[bdrewery]

I'm not sure that is the right place...
There's existing hacks for libc++ in both src/bootstrap/lib.rs and src/librustc_llvm/build.rs.

Modifying the src/bootstrap/lib.rs cflags would achieve the same result as your change I believe. It looks like OpenBSD is missing there too. I wonder why we haven't run into this on FreeBSD in ports or even building from git.

[triaxx]

There was a fix for FreeBSD src/librustc_llvm/build.rs but not in src/bootstrap/lib.rs.

I add it and it now compile. Probably it could be more elegantly written, but I don't know the rust language yet.

$NetBSD$

Don't filter out optimization flags.
FreeBSD has a particular C++ runtime library name

--- src/bootstrap/lib.rs.orig   2018-02-12 18:51:18.000000000 +0000
+++ src/bootstrap/lib.rs
@@ -632,7 +632,6 @@ impl Build {
         // cc-rs because the build scripts will determine that for themselves.
         let mut base = self.cc[&target].args().iter()
                            .map(|s| s.to_string_lossy().into_owned())
-                           .filter(|s| !s.starts_with("-O") && !s.starts_with("/O"))
                            .collect::<Vec<_>>();
 
         // If we're compiling on macOS then we add a few unconditional flags
@@ -643,6 +642,11 @@ impl Build {
             base.push("-stdlib=libc++".into());
         }   
 
+        // FreeBSD (from 10.2) also uses libc++.
+        if target.contains("freebsd") {
+            base.push("-stdlib=libc++".into());
+        }   
+
         // Work around an apparently bad MinGW / GCC optimization,
         // See: http://lists.llvm.org/pipermail/cfe-dev/2016-December/051980.html
         // See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78936

I have now another error:

   Compiling openssl v0.9.23                                        
error[E0463]: can't find crate for `std`                            

error: aborting due to previous error                               

error: Could not compile `openssl`.

But it is unrelated to this issue.

Thank you @bdrewery for your help!