Use `#[link(cfg(..))]` in preparation for libstd
In preparation for rust-lang/rust#37545 this is adding the appropriate
directives to libc to get included.
diff --git a/src/lib.rs b/src/lib.rs
index dcc4791..2bc26aa 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -75,6 +75,7 @@
// Attributes needed when building as part of the standard library
#![cfg_attr(stdbuild, feature(no_std, core, core_slice_ext, staged_api, custom_attribute, cfg_target_vendor))]
+#![cfg_attr(stdbuild, feature(link_cfg))]
#![cfg_attr(stdbuild, no_std)]
#![cfg_attr(stdbuild, staged_api)]
#![cfg_attr(stdbuild, allow(warnings))]
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 0cb3f78..b79bb9f 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -205,7 +205,8 @@
// cargo build, don't pull in anything extra as the libstd dep
// already pulls in all libs.
} else if #[cfg(any(all(target_env = "musl", not(target_arch = "mips"))))] {
- #[link(name = "c", kind = "static")]
+ #[link(name = "c", kind = "static", cfg(target_feature = "crt-static"))]
+ #[link(name = "c", cfg(not(target_feature = "crt-static")))]
extern {}
} else if #[cfg(target_os = "emscripten")] {
#[link(name = "c")]
diff --git a/src/windows.rs b/src/windows.rs
index b916fd4..6c8332a 100644
--- a/src/windows.rs
+++ b/src/windows.rs
@@ -146,8 +146,9 @@
pub const EILSEQ: ::c_int = 42;
pub const STRUNCATE: ::c_int = 80;
-#[cfg(target_env = "msvc")] // " if " -- appease style checker
-#[link(name = "msvcrt")]
+#[cfg(all(target_env = "msvc", stdbuild))] // " if " -- appease style checker
+#[link(name = "msvcrt", cfg(not(target_feature = "crt-static")))]
+#[link(name = "libcmt", cfg(target_feature = "crt-static"))]
extern {}
extern {