test harness: pw roll forward regression fix

MODULE.bazel

diff --git a/MODULE.bazel b/MODULE.bazel
index aa24379..d547fe8 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -30,6 +30,9 @@
         "//third_party/pigweed:integration_tests_armv7m.patch",
         # Stage .bin alongside .elf in system_image_test runfiles.
         "//third_party/pigweed:system_image_test_bin_runfiles.patch",
+        # Fix syscall_defs/syscall_user being gated on userspace_build_enabled,
+        # which breaks userspace=False kernel builds (pigweed regression).
+        "//third_party/pigweed:syscall_no_userspace_constraint.patch",
     ],
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )

target/ast10x0/harness/test_runner.py

diff --git a/target/ast10x0/harness/test_runner.py b/target/ast10x0/harness/test_runner.py
index e04b432..98e536e 100644
--- a/target/ast10x0/harness/test_runner.py
+++ b/target/ast10x0/harness/test_runner.py
@@ -353,7 +353,13 @@
         action="store_true",
         help="Skip GPIO and firmware upload; stream and detokenize UART output only",
     )
-    args = parser.parse_args()
+    args, remaining = parser.parse_known_args()
+
+    if os.environ.get("PW_RUNNER_PASSTHROUGH") == "1":
+        import subprocess
+
+        res = subprocess.run([args.firmware] + remaining)
+        return res.returncode
 
     uart_device = os.environ.get("UART_DEVICE") or config["uart"]["serial_port"]
 

third_party/pigweed/syscall_no_userspace_constraint.patch

diff --git a/third_party/pigweed/syscall_no_userspace_constraint.patch b/third_party/pigweed/syscall_no_userspace_constraint.patch
new file mode 100644
index 0000000..7d917c3
--- /dev/null
+++ b/third_party/pigweed/syscall_no_userspace_constraint.patch
@@ -0,0 +1,39 @@
+--- a/pw_kernel/syscall/BUILD.bazel
++++ b/pw_kernel/syscall/BUILD.bazel
+@@ -14,7 +14,6 @@
+
+ load("@bazel_skylib//lib:selects.bzl", "selects")
+ load("@rules_rust//rust:defs.bzl", "rust_library")
+-load("//pw_kernel:flags.bzl", "KERNEL_TEST_DEPS", "KERNEL_TEST_RUSTC_FLAGS")
+ load("//pw_kernel/arch/arm_cortex_m:defs.bzl", "SUPPORTED_CORTEX_M_CPUS")
+
+ package(default_visibility = ["//visibility:public"])
+@@ -25,16 +24,11 @@
+         "syscall_defs.rs",
+     ],
+     edition = "2024",
+-    rustc_flags = KERNEL_TEST_RUSTC_FLAGS,
+     tags = ["kernel"],
+-    target_compatible_with = select({
+-        "//pw_kernel/userspace:userspace_build_enabled": [],
+-        "//conditions:default": ["@platforms//:incompatible"],
+-    }),
+     deps = [
+         "//pw_status/rust:pw_status",
+         "@rust_crates//:bitflags",
+-    ] + KERNEL_TEST_DEPS,
++    ],
+ )
+
+ rust_library(
+@@ -51,10 +45,6 @@
+     }),
+     edition = "2024",
+     tags = ["kernel"],
+-    target_compatible_with = select({
+-        "//pw_kernel/userspace:userspace_build_enabled": [],
+-        "//conditions:default": ["@platforms//:incompatible"],
+-    }),
+     deps = [
+         ":syscall_defs",
+         "//pw_status/rust:pw_status",