qt: script & webkit depend on BR2_TOOLCHAIN_HAS_SYNC_4

They use __sync_add_and_fetch_4() and other 32-bit atomics, fixes:
http://autobuild.buildroot.net/results/7ac/7acdbc54e26ad2ba4756512614192be0a086f563/

Also remove sparc from supported architectures since it won't grow
atomics support magically.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/qt/Config.in

@@ -407,12 +407,13 @@ config BR2_PACKAGE_QT_NETWORK
 
 config BR2_PACKAGE_QT_ARCH_SUPPORTS_WEBKIT
 	bool
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	# see src/3rdparty/webkit/Source/JavaScriptCore/wtf/Platform.h
 	# see http://lists.busybox.net/pipermail/buildroot/2014-November/112605.html
 	default y if BR2_arc || BR2_arm || BR2_armeb || BR2_i386 || BR2_microblazeel || \
 		BR2_microblazebe || BR2_mips || BR2_mipsel || \
 		(BR2_mips64 || BR2_mips64el) && !BR2_MIPS_NABI32 || BR2_powerpc || \
-		BR2_powerpc64 || BR2_powerpc64le || BR2_sparc || BR2_x86_64
+		BR2_powerpc64 || BR2_powerpc64le || BR2_x86_64
 	# The CodeSourcery SuperH toolchain fails to build Webkit,
 	# with an assertion failure in binutils.
 	default y if (BR2_sh4 || BR2_sh4eb || BR2_sh4a || BR2_sh4aeb) && \
@@ -454,12 +455,13 @@ config BR2_PACKAGE_QT_OPENSSL
 
 config BR2_PACKAGE_QT_ARCH_SUPPORTS_SCRIPT
 	bool
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
 	# see http://lists.busybox.net/pipermail/buildroot/2014-November/112605.html
 	default y if BR2_arc || BR2_arm || BR2_armeb || aarch64 || BR2_i386 || \
 		BR2_microblazeel || BR2_microblazebe || BR2_mips || BR2_mipsel || \
 		BR2_mips64 || BR2_mips64el || BR2_nios2 || BR2_powerpc || \
 		BR2_powerpc64 || BR2_powerpc64le || BR2_sh4 || BR2_sh4eb || \
-		BR2_sh4a || BR2_sh4aeb || BR2_sparc || BR2_x86_64
+		BR2_sh4a || BR2_sh4aeb || BR2_x86_64
 
 config BR2_PACKAGE_QT_SCRIPT
 	bool "Script Module"