openmpi: disallow on sparc

openmpi's configure script refuses to build on Sparc v8 architecture, so
let's disable this package on sparc 32 bits entirely.

Fixes:

 http://autobuild.buildroot.net/results/be6cb8e2437d345b709cf76357a4420e9beadb5c/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/openmpi/Config.in

@@ -1,5 +1,6 @@
 comment "openmpi needs a toolchain w/ dynamic library, NPTL, wchar, C++"
 	depends on BR2_USE_MMU
+	depends on !BR2_sparc
 	depends on BR2_STATIC_LIBS || !BR2_TOOLCHAIN_HAS_THREADS_NPTL \
 		|| !BR2_USE_WCHAR || !BR2_INSTALL_LIBSTDCPP
 
@@ -10,6 +11,9 @@ config BR2_PACKAGE_OPENMPI
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on !BR2_STATIC_LIBS # dlfcn.h
+	# from the configure script: "Sparc v8 target is not supported
+	# in this release of Open MPI"
+	depends on !BR2_sparc
 	help
 	  A High Performance Message Passing Library.