libuv: add dependency on BR2_TOOLCHAIN_HAS_SYNC_4

The libuv library uses __sync atomic built-ins:

$ readelf -a -W output/target/usr/lib/libuv.so.1.0.0 | grep __sync
   122: 00000000     0 NOTYPE  GLOBAL DEFAULT  UND __sync_val_compare_and_swap_4

but this is not currently taken into account in the libuv package,
causing some build failures in packages using libuv as an optional
dependency, such as janus-gateway and mosquitto.

Therefore, this commit updates the libuv package with this additional
dependency.  The reverse dependencies of libuv are also updated: luv, luvi
and moarvm.

Fixes:

 - http://autobuild.buildroot.net/results/bdaa67d763c0d8d377a04529c74f73bee7d4ccef/
   (janus-gateway)

 - http://autobuild.buildroot.net/results/2bc84ba2d1167018e2d48e5183ead22b6425dcf5/
   (mosquitto)

[Peter: drop cmake changes after cmake revert]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libuv/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_LIBUV
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL # pthread_barrier_*
 	depends on BR2_USE_MMU # fork()
 	depends on !BR2_STATIC_LIBS
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	help
 	  libuv is a multi-platform support library with a focus
 	  on asynchronous I/O.
@@ -12,3 +13,4 @@ config BR2_PACKAGE_LIBUV
 comment "libuv needs a toolchain w/ NPTL, dynamic library"
 	depends on !BR2_TOOLCHAIN_HAS_THREADS_NPTL || BR2_STATIC_LIBS
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4

package/luv/Config.in

@@ -4,6 +4,7 @@ config BR2_PACKAGE_LUV
 	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_SYNC_4 # libuv
 	help
 	  libuv bindings for LuaJIT and Lua.
 
@@ -12,3 +13,4 @@ config BR2_PACKAGE_LUV
 comment "luv needs a toolchain w/ NPTL, dynamic library"
 	depends on !BR2_TOOLCHAIN_HAS_THREADS_NPTL || BR2_STATIC_LIBS
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4

package/luvi/Config.in

@@ -4,6 +4,7 @@ config BR2_PACKAGE_LUVI
 	depends on BR2_USE_MMU # libuv
 	depends on !BR2_STATIC_LIBS # libuv
 	depends on BR2_PACKAGE_LUAJIT
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libuv
 	select BR2_PACKAGE_LIBUV
 	select BR2_PACKAGE_LUV
 	help
@@ -25,6 +26,7 @@ config BR2_PACKAGE_LUVI
 comment "luvi needs a toolchain w/ NPTL, dynamic library"
 	depends on !BR2_TOOLCHAIN_HAS_THREADS_NPTL || BR2_STATIC_LIBS
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 
 comment "luvi needs LuaJIT"
 	depends on !BR2_PACKAGE_LUAJIT

package/moarvm/Config.in

@@ -6,6 +6,7 @@ config BR2_PACKAGE_MOARVM
 	depends on BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS # libatomic_ops
 	# needs AO_fetch_compare_and_swap, not implemented for sparcv8/sparcv9
 	depends on !BR2_sparc64 && !BR2_sparc
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4 # libuv
 	select BR2_PACKAGE_LIBUV
 	select BR2_PACKAGE_LIBTOMMATH
 	select BR2_PACKAGE_LIBATOMIC_OPS
@@ -23,4 +24,4 @@ comment "moarvm needs a toolchain w/ NPTL, dynamic library"
 	depends on BR2_USE_MMU
 	depends on BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS
 	depends on !BR2_sparc64 && !BR2_sparc
-
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4