diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0b5b3ac651..38aa660d4d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -31,7 +31,7 @@ test_build_system:
   variables:
     IDF_PATH: "$CI_PROJECT_DIR"
   script:
-    - ./make/build_system_tests.sh
+    - ./make/test_build_system.sh
 
 push_master_to_github:
   stage: deploy
diff --git a/components/freertos/include/freertos/task.h b/components/freertos/include/freertos/task.h
index d771ca6539..ddf7a7589d 100644
--- a/components/freertos/include/freertos/task.h
+++ b/components/freertos/include/freertos/task.h
@@ -75,6 +75,8 @@
 	#error "include FreeRTOS.h must appear in source files before include task.h"
 #endif
 
+#include <limits.h>
+
 #include "list.h"
 #include "portmacro.h"
 
@@ -91,7 +93,7 @@ extern "C" {
 #define tskKERNEL_VERSION_MINOR 2
 #define tskKERNEL_VERSION_BUILD 0
 
-#define tskNO_AFFINITY portNUM_PROCESSORS
+#define tskNO_AFFINITY INT_MAX
 
 /**
  * task. h
diff --git a/make/build_system_tests.sh b/make/test_build_system.sh
similarity index 91%
rename from make/build_system_tests.sh
rename to make/test_build_system.sh
index 5824cf2b8e..5de216dea3 100755
--- a/make/build_system_tests.sh
+++ b/make/test_build_system.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# Build system tests
+# Test the build system for basic consistency
 #
 # Just a bash script that tests some likely make failure scenarios in a row
 # Creates its own test build directory under TMP and cleans it up when done.
@@ -131,6 +131,18 @@ function assert_built()
 	done
 }
 
+# Test if a file has been rebuilt.
+function file_was_rebuilt()
+{
+	# can't use [ a -ot b ] here as -ot only gives second resolution
+	# but stat -c %y seems to be microsecond at least for tmpfs, ext4..
+	if [ "$(stat -c %y ${SNAPSHOT}/$1)" != "$(stat -c %y ${BUILD}/$1)" ]; then
+		return 0
+	else
+		return 1
+	fi
+}
+
 # verify all the arguments passed in were rebuilt relative to the snapshot
 function assert_rebuilt()
 {
@@ -139,7 +151,7 @@ function assert_rebuilt()
 		if [ ! -f "${SNAPSHOT}/$1" ]; then
 			failure "File $1 should have been original build snapshot"
 		fi
-		if [ ! "${SNAPSHOT}/$1" -ot "${BUILD}/$1" ]; then
+		if ! file_was_rebuilt "$1"; then
 			failure "File $1 should have been rebuilt"
 		fi
 		shift
@@ -155,7 +167,7 @@ function assert_not_rebuilt()
 		if [ ! -f "${SNAPSHOT}/$1" ]; then
 			failure "File $1 should be in snapshot build directory"
 		fi
-		if [ "${SNAPSHOT}/$1" -ot "${BUILD}/$1" ]; then
+		if file_was_rebuilt "$1"; then
 			failure "File $1 should not have been rebuilt"
 		fi
 		shift