diff --git a/.github/workflows/cross-bootstrap-tools.yml b/.github/workflows/cross-bootstrap-tools.yml
index 9aa2b7cb6c..69e05e0035 100644
--- a/.github/workflows/cross-bootstrap-tools.yml
+++ b/.github/workflows/cross-bootstrap-tools.yml
@@ -67,8 +67,4 @@ jobs:
             args+=($EXTRA_BUILD_ARGS)
           fi
           args+=(TARGET=${{ matrix.target }} TARGET_ARCH=${{ matrix.target_arch }} KERNCONF=GENERIC NO_MODULES=yes buildkernel -s -j"$NPROC")
-          if [ "${{ runner.os }}" = "Linux" ] && [ "${{ matrix.target_arch }}" = "aarch64" ]; then
-            resource_dir=$(/usr/lib/llvm-18/bin/clang -print-resource-dir)
-            args+=("KERNEL_FLAGS=CFLAGS+=-idirafter ${PWD}/tools/build/cross-build/include/common CFLAGS+=-idirafter ${resource_dir}/include")
-          fi
           "${args[@]}"
diff --git a/sys/contrib/ck/include/ck_stdbool.h b/sys/contrib/ck/include/ck_stdbool.h
index 6af26ab4fa..d00f367669 100644
--- a/sys/contrib/ck/include/ck_stdbool.h
+++ b/sys/contrib/ck/include/ck_stdbool.h
@@ -24,7 +24,7 @@
  * SUCH DAMAGE.
  */
 
-#if defined(__MidnightBSD__) && defined(_KERNEL)
+#if defined(_KERNEL)	/* any BSD kernel build; compiler may not predefine __MidnightBSD__/__FreeBSD__ */
 #include <sys/types.h>
 #else
 #include <stdbool.h>
diff --git a/sys/contrib/ck/include/ck_stddef.h b/sys/contrib/ck/include/ck_stddef.h
index ab5868001b..a7e487b538 100644
--- a/sys/contrib/ck/include/ck_stddef.h
+++ b/sys/contrib/ck/include/ck_stddef.h
@@ -24,7 +24,7 @@
  * SUCH DAMAGE.
  */
 
-#if defined(__MidnightBSD__) && defined(_KERNEL)
+#if defined(_KERNEL)	/* any BSD kernel build; compiler may not predefine __MidnightBSD__/__FreeBSD__ */
 #include <sys/stddef.h>
 #else
 #include <stddef.h>
diff --git a/sys/contrib/ck/include/ck_stdint.h b/sys/contrib/ck/include/ck_stdint.h
index 7398d8cfaf..f88426b13f 100644
--- a/sys/contrib/ck/include/ck_stdint.h
+++ b/sys/contrib/ck/include/ck_stdint.h
@@ -27,7 +27,7 @@
 #if defined(__linux__) && (defined(__KERNEL__) || defined(_KERNEL))
 #include <linux/kernel.h>
 #include <linux/types.h>
-#elif defined(__MidnightBSD__) && defined(_KERNEL)
+#elif defined(_KERNEL)	/* any BSD kernel build; compiler may not predefine __MidnightBSD__/__FreeBSD__ */
 #include <sys/stdint.h>
 #else
 #include <stdint.h>
diff --git a/sys/contrib/ck/include/ck_stdlib.h b/sys/contrib/ck/include/ck_stdlib.h
index a8555104ad..aede9ec1ae 100644
--- a/sys/contrib/ck/include/ck_stdlib.h
+++ b/sys/contrib/ck/include/ck_stdlib.h
@@ -24,7 +24,7 @@
  * SUCH DAMAGE.
  */
 
-#if defined(__MidnightBSD__) && defined(_KERNEL)
+#if defined(_KERNEL)	/* any BSD kernel build; compiler may not predefine __MidnightBSD__/__FreeBSD__ */
 #include <sys/systm.h>
 #else
 #include <stdlib.h>
diff --git a/sys/contrib/ck/include/ck_string.h b/sys/contrib/ck/include/ck_string.h
index 6b0978103a..238953ef37 100644
--- a/sys/contrib/ck/include/ck_string.h
+++ b/sys/contrib/ck/include/ck_string.h
@@ -24,7 +24,7 @@
  * SUCH DAMAGE.
  */
 
-#if defined(__MidnightBSD__) && defined(_KERNEL)
+#if defined(_KERNEL)	/* any BSD kernel build; compiler may not predefine __MidnightBSD__/__FreeBSD__ */
 #include <sys/systm.h>
 #else
 #include <string.h>