package/boost: disable logs with riscv32

boost logs can't be built with riscv32 because it unconditionally uses
__NR_futex:

libs/log/src/event.cpp: In member function 'void boost::log::v2_mt_posix::aux::futex_based_event::wait()':
libs/log/src/event.cpp:38:29: error: '__NR_futex' was not declared in this scope
   38 | #define BOOST_LOG_SYS_FUTEX __NR_futex
      |                             ^~~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/8c8135fd7c0517c66c9b3975c494da6d7934cc1b

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/azmq/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_AZMQ
 	bool "azmq"
+	depends on !BR2_RISCV_32 # boost-log
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_ATOMIC
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL # boost-log
@@ -22,9 +23,11 @@ config BR2_PACKAGE_AZMQ
 	  https://github.com/zeromq/azmq
 
 comment "azmq needs a toolchain w/ C++11, wchar and NPTL"
+	depends on !BR2_RISCV_32
 	depends on BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS
 	depends on !(BR2_INSTALL_LIBSTDCPP && BR2_TOOLCHAIN_GCC_AT_LEAST_4_8 \
 		&& BR2_USE_WCHAR && BR2_TOOLCHAIN_HAS_THREADS_NPTL)
 
 comment "azmq needs exception_ptr"
+	depends on !BR2_RISCV_32
 	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735

package/boost/Config.in

@@ -231,6 +231,7 @@ comment "boost-locale needs a toolchain not affected by GCC bug 64735"
 
 config BR2_PACKAGE_BOOST_LOG
 	bool "boost-log"
+	depends on !BR2_RISCV_32
 	depends on BR2_TOOLCHAIN_HAS_THREADS_NPTL
 	depends on BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS # boost-atomic
 	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # boost-thread
@@ -244,10 +245,12 @@ config BR2_PACKAGE_BOOST_LOG
 	  Logging library.
 
 comment "boost-log needs a toolchain w/ NPTL"
+	depends on !BR2_RISCV_32
 	depends on BR2_TOOLCHAIN_SUPPORTS_ALWAYS_LOCKFREE_ATOMIC_INTS
 	depends on !BR2_TOOLCHAIN_HAS_THREADS_NPTL
 
 comment "boost-log needs a toolchain not affected by GCC bug 64735"
+	depends on !BR2_RISCV_32
 	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735
 
 config BR2_PACKAGE_BOOST_MATH