Set platform and toolchain flags to canonicalized for cquery/aquery

Test: USE_BAZEL=1 USE_BAZEL_ANALYSIS=1 m libc
Change-Id: If9194d5e00d4d53a3c012ea2d602f0b8e73213c7
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index 4a25119..5ba6d62 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -234,6 +234,13 @@
 	cmdFlags = append(cmdFlags, labels...)
 	cmdFlags = append(cmdFlags, "--package_path=%workspace%/"+context.intermediatesDir())
 	cmdFlags = append(cmdFlags, "--profile="+shared.BazelMetricsFilename(context, runName))
+	// Set default platforms to canonicalized values for mixed builds requests. If these are set
+	// in the bazelrc, they will have values that are non-canonicalized, and thus be invalid.
+	// The actual platform values here may be overridden by configuration transitions from the buildroot.
+	cmdFlags = append(cmdFlags,
+		fmt.Sprintf("--platforms=%s", canonicalizeLabel("//build/bazel/platforms:generic_x86_64")))
+	cmdFlags = append(cmdFlags,
+		fmt.Sprintf("--extra_toolchains=%s", canonicalizeLabel("//prebuilts/clang/host/linux-x86:all")))
 	cmdFlags = append(cmdFlags, extraFlags...)
 
 	bazelCmd := exec.Command(context.bazelPath, cmdFlags...)