compiletest: Match suffixed environments

This fixes a case where an `ignore-musl` test was not ignored on
`armv7-unknown-linux-musleabihf` because the environment did not exactly
match. Only enforce that the environment starts with the argument to
`ignore-`.

src/tools/compiletest/src/header.rs

@@ -835,10 +835,10 @@ impl Config {
 
             if name == "test" ||
                 util::matches_os(&self.target, name) ||             // target
+                util::matches_env(&self.target, name) ||            // env
                 name == util::get_arch(&self.target) ||             // architecture
                 name == util::get_pointer_width(&self.target) ||    // pointer width
                 name == self.stage_id.split('-').next().unwrap() || // stage
-                Some(name) == util::get_env(&self.target) ||        // env
                 (self.target != self.host && name == "cross-compile") ||
                 match self.compare_mode {
                     Some(CompareMode::Nll) => name == "compare-mode-nll",

src/tools/compiletest/src/util.rs

@@ -105,8 +105,12 @@ pub fn get_arch(triple: &str) -> &'static str {
     panic!("Cannot determine Architecture from triple");
 }
 
-pub fn get_env(triple: &str) -> Option<&str> {
-    triple.split('-').nth(3)
+pub fn matches_env(triple: &str, name: &str) -> bool {
+    if let Some(env) = triple.split('-').nth(3) {
+        env.starts_with(name)
+    } else {
+        false
+    }
 }
 
 pub fn get_pointer_width(triple: &str) -> &'static str {