Disable has_reliable_f128_math on musl targets

musl does not implement the symbols required by std for f128 maths.
Disable the associated cfg for all musl targets and adjust the tests
accordingly.

Signed-off-by: Jens Reidel <[email protected]>

Author: Gelbpunkt

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -436,7 +436,8 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
         ("x86_64", _) => false,
         (_, "linux") if target_pointer_width == 64 => true,
         _ => false,
-    } && cfg.has_reliable_f128;
+    } && cfg.has_reliable_f128
+        && target_env != "musl";
 }
 
 pub(crate) fn print_version() {

tests/ui/float/target-has-reliable-nightly-float.rs

@@ -19,8 +19,10 @@ pub fn has_f128() {}
 pub fn has_f128_math() {}
 
 fn main() {
-    if cfg!(target_arch = "aarch64") && cfg!(target_os = "linux") {
-        // Aarch64+Linux is one target that has support for all features, so use it to spot
+    if cfg!(target_arch = "aarch64") &&
+        cfg!(target_os = "linux") &&
+        cfg!(not(target_env = "musl")) {
+        // Aarch64+GNU+Linux is one target that has support for all features, so use it to spot
         // check that the compiler does indeed enable these gates.
 
         assert!(cfg!(target_has_reliable_f16));