remove vestigial BuildConfig flags

Author: Xaeroxe

src/cargo/core/compiler/build_config.rs

@@ -48,8 +48,6 @@ pub struct BuildConfig {
     pub future_incompat_report: bool,
     /// Which kinds of build timings to output (empty if none).
     pub timing_outputs: Vec<TimingOutput>,
-    /// Use checksums rather than mtimes to determine if a crate is fresh.
-    pub checksum_freshness: bool,
 }
 
 fn default_parallelism() -> CargoResult<u32> {
@@ -122,7 +120,6 @@ impl BuildConfig {
             export_dir: None,
             future_incompat_report: false,
             timing_outputs: Vec::new(),
-            checksum_freshness: false,
         })
     }
 

src/cargo/util/command_prelude.rs

@@ -759,7 +759,6 @@ Run `{cmd}` to see possible targets."
         build_config.build_plan = self.flag("build-plan");
         build_config.unit_graph = self.flag("unit-graph");
         build_config.future_incompat_report = self.flag("future-incompat-report");
-        build_config.checksum_freshness = self.flag("checksum-freshness");
 
         if self._contains("timings") {
             for timing_output in self._values_of("timings") {
@@ -794,10 +793,6 @@ Run `{cmd}` to see possible targets."
             gctx.cli_unstable()
                 .fail_if_stable_opt("--unit-graph", 8002)?;
         }
-        if build_config.checksum_freshness {
-            gctx.cli_unstable()
-                .fail_if_stable_opt("--checksum-freshness", 14136)?;
-        }
 
         let opts = CompileOptions {
             build_config,