diff --git a/package/libfastjson/Config.in b/package/libfastjson/Config.in
index 5a9411332f..fbc9b1d68a 100644
--- a/package/libfastjson/Config.in
+++ b/package/libfastjson/Config.in
@@ -1,7 +1,7 @@
 config BR2_PACKAGE_LIBFASTJSON
 	bool "libfastjson"
-	# uses __sync_val_compare_and_swap_4
-	depends on BR2_TOOLCHAIN_HAS_SYNC_4
+	# uses the __sync_*_4 intrisics, or pthreads to emulate atomicity
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 || BR2_TOOLCHAIN_HAS_THREADS
 	help
 	  Libfastjson - A fast json library for C
 
diff --git a/package/rsyslog/Config.in b/package/rsyslog/Config.in
index 65291deae3..b3c146dc86 100644
--- a/package/rsyslog/Config.in
+++ b/package/rsyslog/Config.in
@@ -7,7 +7,9 @@ config BR2_PACKAGE_RSYSLOG
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_USE_MMU # fork()
 	depends on !BR2_STATIC_LIBS # modules
-	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libfastjson
+	# Propagate the exact same dependency from libfastjson,
+	# even though rsyslog already depends on threads for itself:
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 || BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
 	help
 	  Rsyslog is a powerful and flexible syslog implementation
@@ -18,4 +20,4 @@ comment "rsyslog needs a toolchain w/ threads, dynamic library"
 	depends on BR2_USE_MMU
 	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on !BR2_TOOLCHAIN_HAS_THREADS || BR2_STATIC_LIBS
-	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
\ No newline at end of file
+	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS