package/boost: upstream patch to re-enable logs with riscv32

Commit d72350e62a0833e4d1527f4040da2063972bf9b3 disabled boost::logs on
riscv32 due to the use of SYS_futex, which doesn't exist on riscv32.

Revert "package/boost: disable logs with riscv32" and add an upstream
patch that uses SYS_futex_time64 instead.

This reverts commit d72350e62a0833e4d1527f4040da2063972bf9b3.

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

package/azmq/Config.in

@@ -1,6 +1,5 @@
 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
@@ -23,11 +22,9 @@ 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/0002-src-event-cpp-fix-build-on-riscv32.patch

@@ -0,0 +1,42 @@
+From d2061419501bdd6761e9380ed5b91233f6c4e67e Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Fri, 21 May 2021 21:30:04 +0200
+Subject: [PATCH] src/event.cpp: fix build on riscv32
+
+riscv32 fails to build because __NR_futex is not defined on this
+architecture:
+
+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>
+[Retrieved from:
+https://github.com/boostorg/log/commit/d2061419501bdd6761e9380ed5b91233f6c4e67e]
+---
+ src/event.cpp | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/libs/log/src/event.cpp b/libs/log/src/event.cpp
+index 5485154d7..f576648c6 100644
+--- a/libs/log/src/event.cpp
++++ b/libs/log/src/event.cpp
+@@ -34,8 +34,13 @@
+ // Some Android NDKs (Google NDK and older Crystax.NET NDK versions) don't define SYS_futex
+ #if defined(SYS_futex)
+ #define BOOST_LOG_SYS_FUTEX SYS_futex
+-#else
++#elif defined(__NR_futex)
+ #define BOOST_LOG_SYS_FUTEX __NR_futex
++// riscv32 defines a different system call instead of __NR_futex
++#elif defined(__NR_futex_time64)
++#define BOOST_LOG_SYS_FUTEX __NR_futex_time64
++#else
++#error "Unable to find a suitable futex"
+ #endif
+ 
+ #if defined(FUTEX_WAIT_PRIVATE)

package/boost/Config.in

@@ -231,7 +231,6 @@ 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
@@ -245,12 +244,10 @@ 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