[lldb] fix arm64e tests not compiling with an arm64e target

Author: charles-zablit

lldb/packages/Python/lldbsuite/test/lldbarm64e.py

@@ -6,6 +6,14 @@
 @skipUnlessArm64eSupported
 class Arm64eTestBase(TestBase):
     def build(self):
+        triple = configuration.triple.replace("arm64-", "arm64e-")
+        # ARCH_CFLAGS is a Make command-line variable set by the test harness
+        # to a plain (non-arm64e) `-mtargetos=...` flag. A plain in-Makefile
+        # assignment can't override a command-line variable, so overriding
+        # TRIPLE alone leaves the compiler without an explicit `-target`
+        # flag and it silently falls back to the host's default (non-arm64e)
+        # triple. Override ARCH_CFLAGS too so it wins as a later command-line
+        # definition.
         super().build(
-            dictionary={"TRIPLE": configuration.triple.replace("arm64-", "arm64e-")}
+            dictionary={"TRIPLE": triple, "ARCH_CFLAGS": "-target " + triple}
         )