wampcc: needs atomic

Fixes:
 - http://autobuild.buildroot.net/results/2f994762d4e01a904c50cf2728a4103e6e79da2a

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/wampcc/Config.in

@@ -4,6 +4,7 @@ config BR2_PACKAGE_WAMPCC
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL # libuv
 	depends on BR2_USE_MMU # libuv
 	depends on !BR2_STATIC_LIBS # libuv
+	depends on BR2_TOOLCHAIN_HAS_ATOMIC
 	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libuv
 	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # std::shared_future
 	select BR2_PACKAGE_LIBUV
@@ -17,11 +18,13 @@ config BR2_PACKAGE_WAMPCC
 
 comment "wampcc needs a toolchain w/ C++, NPTL, dynamic library"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_ATOMIC
 	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on !BR2_INSTALL_LIBSTDCPP || \
 		!BR2_TOOLCHAIN_HAS_THREADS_NPTL || BR2_STATIC_LIBS
 
 comment "wampcc needs a toolchain not affected by GCC bug 64735"
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_ATOMIC
 	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735

package/wampcc/wampcc.mk

@@ -11,4 +11,9 @@ WAMPCC_INSTALL_STAGING = YES
 WAMPCC_LICENSE = MIT
 WAMPCC_LICENSE_FILES = LICENSE
 
+# Uses __atomic_fetch_add_8
+ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
+WAMPCC_CONF_OPTS += -DCMAKE_CXX_FLAGS="$(TARGET_CXXFLAGS) -latomic"
+endif
+
 $(eval $(cmake-package))