bootstrap: Add directives to not double-link libs

Have all Cargo-built crates pass `--cfg cargobuild` and then add appropriate
`#[cfg]` definitions to all crates to avoid linking anything if this is passed.
This should help allow libstd to compile with both the makefiles and with Cargo.

15 files changed, 38 insertions, 5 deletions

diff --git a/src/liballoc_jemalloc/build.rs b/src/liballoc_jemalloc/build.rs
index 18f0527425a..4bc752af48e 100644
--- a/src/liballoc_jemalloc/build.rs
+++ b/src/liballoc_jemalloc/build.rs
@@ -17,6 +17,8 @@ use std::process::Command;
 use build_helper::run;
 
 fn main() {
+    println!("cargo:rustc-cfg=cargobuild");
+
     let target = env::var("TARGET").unwrap();
     let host = env::var("HOST").unwrap();
     let build_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
diff --git a/src/liballoc_jemalloc/lib.rs b/src/liballoc_jemalloc/lib.rs
index d02e9e4ba13..2c46e37ac32 100644
--- a/src/liballoc_jemalloc/lib.rs
+++ b/src/liballoc_jemalloc/lib.rs
@@ -38,7 +38,10 @@ use libc::{c_int, c_void, size_t};
                not(target_os = "android"),
                not(target_env = "musl")),
            link(name = "pthread"))]
-extern "C" {
+#[cfg(not(cargobuild))]
+extern {}
+
+extern {
     fn je_mallocx(size: size_t, flags: c_int) -> *mut c_void;
     fn je_rallocx(ptr: *mut c_void, size: size_t, flags: c_int) -> *mut c_void;
     fn je_xallocx(ptr: *mut c_void, size: size_t, extra: size_t, flags: c_int) -> size_t;
diff --git a/src/libflate/build.rs b/src/libflate/build.rs
index 12016980a2c..245c705dfcc 100644
--- a/src/libflate/build.rs
+++ b/src/libflate/build.rs
@@ -11,6 +11,7 @@
 extern crate gcc;
 
 fn main() {
+    println!("cargo:rustc-cfg=cargobuild");
     gcc::Config::new()
         .file("../rt/miniz.c")
         .compile("libminiz.a");
diff --git a/src/libflate/lib.rs b/src/libflate/lib.rs
index f316250d96d..a6bf735e459 100644
--- a/src/libflate/lib.rs
+++ b/src/libflate/lib.rs
@@ -79,7 +79,10 @@ impl Drop for Bytes {
 }
 
 #[link(name = "miniz", kind = "static")]
-extern "C" {
+#[cfg(not(cargobuild))]
+extern {}
+
+extern {
     /// Raw miniz compression function.
     fn tdefl_compress_mem_to_heap(psrc_buf: *const c_void,
                                   src_buf_len: size_t,
diff --git a/src/librustc_llvm/build.rs b/src/librustc_llvm/build.rs
index 4f2fee6943f..1c9982790cf 100644
--- a/src/librustc_llvm/build.rs
+++ b/src/librustc_llvm/build.rs
@@ -18,6 +18,8 @@ use std::path::PathBuf;
 use build_helper::output;
 
 fn main() {
+    println!("cargo:rustc-cfg=cargobuild");
+
     let target = env::var("TARGET").unwrap();
     let llvm_config = env::var_os("LLVM_CONFIG").map(PathBuf::from)
                            .unwrap_or_else(|| {
diff --git a/src/librustc_llvm/lib.rs b/src/librustc_llvm/lib.rs
index 059287ccb5e..8877479104e 100644
--- a/src/librustc_llvm/lib.rs
+++ b/src/librustc_llvm/lib.rs
@@ -609,6 +609,9 @@ pub mod debuginfo {
 // automatically updated whenever LLVM is updated to include an up-to-date
 // set of the libraries we need to link to LLVM for.
 #[link(name = "rustllvm", kind = "static")]
+#[cfg(not(cargobuild))]
+extern {}
+
 #[linked_from = "rustllvm"] // not quite true but good enough
 extern {
     /* Create and destroy contexts. */
@@ -2486,6 +2489,7 @@ impl Drop for OperandBundleDef {
 // parts of LLVM that rustllvm depends on aren't thrown away by the linker.
 // Works to the above fix for #15460 to ensure LLVM dependencies that
 // are only used by rustllvm don't get stripped by the linker.
+#[cfg(not(cargobuild))]
 mod llvmdeps {
     include! { env!("CFG_LLVM_LINKAGE_FILE") }
 }
diff --git a/src/librustdoc/build.rs b/src/librustdoc/build.rs
index fcb7af11dce..171954f325a 100644
--- a/src/librustdoc/build.rs
+++ b/src/librustdoc/build.rs
@@ -11,6 +11,7 @@
 extern crate gcc;
 
 fn main() {
+    println!("cargo:rustc-cfg=cargobuild");
     let mut cfg = gcc::Config::new();
     cfg.file("../rt/hoedown/src/autolink.c")
        .file("../rt/hoedown/src/buffer.c")
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index a5436886a7e..c0846cae687 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -157,6 +157,9 @@ struct hoedown_buffer {
 
 // hoedown FFI
 #[link(name = "hoedown", kind = "static")]
+#[cfg(not(cargobuild))]
+extern {}
+
 extern {
     fn hoedown_html_renderer_new(render_flags: libc::c_uint,
                                  nesting_level: libc::c_int)
diff --git a/src/libstd/build.rs b/src/libstd/build.rs
index 8561d53a0d3..8fb49a1be4e 100644
--- a/src/libstd/build.rs
+++ b/src/libstd/build.rs
@@ -19,6 +19,8 @@ use std::process::Command;
 use build_helper::run;
 
 fn main() {
+    println!("cargo:rustc-cfg=cargobuild");
+
     let target = env::var("TARGET").unwrap();
     let host = env::var("HOST").unwrap();
     if !target.contains("apple") && !target.contains("msvc") {
diff --git a/src/libstd/rand/os.rs b/src/libstd/rand/os.rs
index 8d92909faf5..8a422246514 100644
--- a/src/libstd/rand/os.rs
+++ b/src/libstd/rand/os.rs
@@ -269,7 +269,10 @@ mod imp {
     const kSecRandomDefault: *const SecRandom = ptr::null();
 
     #[link(name = "Security", kind = "framework")]
-    extern "C" {
+    #[cfg(not(cargobuild))]
+    extern {}
+
+    extern {
         fn SecRandomCopyBytes(rnd: *const SecRandom,
                               count: size_t, bytes: *mut u8) -> c_int;
     }
diff --git a/src/libstd/rtdeps.rs b/src/libstd/rtdeps.rs
index b1b9ffc4dc6..a11200873d5 100644
--- a/src/libstd/rtdeps.rs
+++ b/src/libstd/rtdeps.rs
@@ -12,6 +12,8 @@
 //! the standard library This varies per-platform, but these libraries are
 //! necessary for running libstd.
 
+#![cfg(not(cargobuild))]
+
 // LLVM implements the `frem` instruction as a call to `fmod`, which lives in
 // libm. Hence, we must explicitly link to it.
 //
diff --git a/src/libstd/sys/common/gnu/libbacktrace.rs b/src/libstd/sys/common/gnu/libbacktrace.rs
index f8463388384..8b3cb04030c 100644
--- a/src/libstd/sys/common/gnu/libbacktrace.rs
+++ b/src/libstd/sys/common/gnu/libbacktrace.rs
@@ -40,7 +40,7 @@ pub fn print(w: &mut Write, idx: isize, addr: *mut libc::c_void,
                       errnum: libc::c_int);
     enum backtrace_state {}
     #[link(name = "backtrace", kind = "static")]
-    #[cfg(not(test))]
+    #[cfg(all(not(test), not(cargobuild)))]
     extern {}
 
     extern {
diff --git a/src/libstd/sys/common/unwind/gcc.rs b/src/libstd/sys/common/unwind/gcc.rs
index 12cd07a4f4f..7cf9e2a54bd 100644
--- a/src/libstd/sys/common/unwind/gcc.rs
+++ b/src/libstd/sys/common/unwind/gcc.rs
@@ -252,6 +252,9 @@ pub mod eh_frame_registry {
     // See also: rtbegin.rs, `unwind` module.
 
     #[link(name = "gcc_eh")]
+    #[cfg(not(cargobuild))]
+    extern {}
+
     extern {
         fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8);
         fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8);
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 9def3adc303..b6a0bd84409 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -339,7 +339,6 @@ pub fn args() -> Args {
 pub fn args() -> Args {
     use mem;
 
-    #[link(name = "objc")]
     extern {
         fn sel_registerName(name: *const libc::c_uchar) -> Sel;
         fn objc_msgSend(obj: NsId, sel: Sel, ...) -> NsId;
@@ -347,6 +346,8 @@ pub fn args() -> Args {
     }
 
     #[link(name = "Foundation", kind = "framework")]
+    #[link(name = "objc")]
+    #[cfg(not(cargobuild))]
     extern {}
 
     type Sel = *const libc::c_void;
diff --git a/src/libstd/sys/windows/c.rs b/src/libstd/sys/windows/c.rs
index 6e8090a2235..9fdeb0aef14 100644
--- a/src/libstd/sys/windows/c.rs
+++ b/src/libstd/sys/windows/c.rs
@@ -966,6 +966,9 @@ pub enum EXCEPTION_DISPOSITION {
 #[link(name = "userenv")]
 #[link(name = "shell32")]
 #[link(name = "advapi32")]
+#[cfg(not(cargobuild))]
+extern {}
+
 extern "system" {
     pub fn WSAStartup(wVersionRequested: WORD,
                       lpWSAData: LPWSADATA) -> c_int;