diff --git a/package/frr/Config.in b/package/frr/Config.in
index 911913292f..877b75b107 100644
--- a/package/frr/Config.in
+++ b/package/frr/Config.in
@@ -3,7 +3,7 @@ config BR2_PACKAGE_FRR
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on !BR2_STATIC_LIBS # libyang
 	depends on BR2_USE_MMU # fork()
-	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # json-c
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # json-c, libyang
 	select BR2_PACKAGE_BASH
 	select BR2_PACKAGE_BUSYBOX_SHOW_OTHERS # bash
 	select BR2_PACKAGE_C_ARES
diff --git a/package/libnetconf2/Config.in b/package/libnetconf2/Config.in
index 0a735b5ed6..7865f9e487 100644
--- a/package/libnetconf2/Config.in
+++ b/package/libnetconf2/Config.in
@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBNETCONF2
 	bool "libnetconf2"
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libyang
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on !BR2_STATIC_LIBS
 	depends on BR2_USE_MMU
@@ -12,4 +13,5 @@ config BR2_PACKAGE_LIBNETCONF2
 
 comment "libnetconf2 needs a toolchain w/ threads, dynamic libraray"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on BR2_STATIC_LIBS || !BR2_TOOLCHAIN_HAS_THREADS
diff --git a/package/libyang/Config.in b/package/libyang/Config.in
index 54df061b58..d08f8fd42f 100644
--- a/package/libyang/Config.in
+++ b/package/libyang/Config.in
@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBYANG
 	bool "libyang"
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # __sync_*_4 intrinsics
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on !BR2_STATIC_LIBS
 	select BR2_PACKAGE_PCRE2
@@ -10,4 +11,5 @@ config BR2_PACKAGE_LIBYANG
 	  https://github.com/CESNET/libyang
 
 comment "libyang needs a toolchain w/ threads, dynamic library"
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on !BR2_TOOLCHAIN_HAS_THREADS || BR2_STATIC_LIBS
diff --git a/package/netopeer2/Config.in b/package/netopeer2/Config.in
index 763b1f234b..db31a786a1 100644
--- a/package/netopeer2/Config.in
+++ b/package/netopeer2/Config.in
@@ -1,11 +1,13 @@
 comment "netopeer2 needs a toolchain w/ gcc >= 4.8, C++, threads, dynamic library"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on BR2_STATIC_LIBS || !BR2_INSTALL_LIBSTDCPP \
 		|| !BR2_TOOLCHAIN_HAS_THREADS_NPTL || !BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
 
 config BR2_PACKAGE_NETOPEER2
 	bool "netopeer2"
 	depends on BR2_USE_MMU # libnetconf2, libssh, sysrepo
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libyang
 	depends on !BR2_STATIC_LIBS # libnetconf2, libssh, libyang, sysrepo
 	depends on BR2_INSTALL_LIBSTDCPP # sysrepo
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL
diff --git a/package/sysrepo/Config.in b/package/sysrepo/Config.in
index 52df1bc4c3..b1535bed9f 100644
--- a/package/sysrepo/Config.in
+++ b/package/sysrepo/Config.in
@@ -1,6 +1,7 @@
 config BR2_PACKAGE_SYSREPO
 	bool "sysrepo"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libyang
 	depends on !BR2_STATIC_LIBS
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL
@@ -24,5 +25,6 @@ endif
 
 comment "sysrepo needs a toolchain w/ C++, NPTL, dynamic library, gcc >= 4.8"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on BR2_STATIC_LIBS || !BR2_INSTALL_LIBSTDCPP \
 		|| !BR2_TOOLCHAIN_HAS_THREADS_NPTL