rust: synchronize patches with merged PR

See rust-lang/rust#105920
No revbump since installed files will not change.

lang/rust/Portfile

@@ -84,9 +84,8 @@ post-extract {
 }
 
 patchfiles-append           patch-offline_bootstrap.diff \
-                            patch-configure.py.diff \
+                            patch-UsingTheRightCompiler.diff \
                             patch-i686_to_i386.diff \
-                            patch-macports_linker.diff \
                             patch-emulate_tls.diff
 if { ${rust.use_cctools} } {
     patchfiles-append       patch-llvm_libtool.diff

lang/rust/files/patch-UsingTheRightCompiler.diff

@@ -0,0 +1,29 @@
+See https://github.com/rust-lang/rust/pull/105920
+
+--- src/bootstrap/bootstrap.py
++++ src/bootstrap/bootstrap.py
+@@ -752,6 +752,9 @@ def build_bootstrap(self, color):
+             target_features += ["-crt-static"]
+         if target_features:
+             env["RUSTFLAGS"] += " -C target-feature=" + (",".join(target_features))
++        target_linker = self.get_toml("linker", build_section)
++        if target_linker is not None:
++            env["RUSTFLAGS"] += " -C linker=" + target_linker
+         env["RUSTFLAGS"] += " -Wrust_2018_idioms -Wunused_lifetimes"
+         env["RUSTFLAGS"] += " -Wsemicolon_in_expressions_from_macros"
+         if self.get_toml("deny-warnings", "rust") != "false":
+diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
+index 6b139decb5551..31cc4aa57bbea 100755
+--- src/bootstrap/configure.py
++++ src/bootstrap/configure.py
+@@ -405,7 +405,9 @@ def set(key, value):
+         configured_targets.append(target)
+ for target in configured_targets:
+     targets[target] = sections['target'][:]
+-    targets[target][0] = targets[target][0].replace("x86_64-unknown-linux-gnu", "'{}'".format(target))
++    # For `.` to be valid TOML, it needs to be quoted. But `bootstrap.py` doesn't use a proper TOML parser and fails to parse the target.
++    # Avoid using quotes unless it's necessary.
++    targets[target][0] = targets[target][0].replace("x86_64-unknown-linux-gnu", "'{}'".format(target) if "." in target else target)
+
+
+ def is_number(value):