* update build2 to 0.16.0-2

build2/atomic-non-lock-free.patch

@@ -0,0 +1,47 @@
+--- build2-toolchain-0.16.0/build2/libbuild2/target.hxx.orig	2024-01-16 14:14:32.696119639 +0100
++++ build2-toolchain-0.16.0/build2/libbuild2/target.hxx	2024-01-16 14:14:39.103465932 +0100
+@@ -4,6 +4,8 @@
+ #ifndef LIBBUILD2_TARGET_HXX
+ #define LIBBUILD2_TARGET_HXX
+ 
++#define LIBBUILD2_ATOMIC_NON_LOCK_FREE
++
+ #include <cstddef>      // max_align_t
+ #include <iterator>     // tags, etc.
+ #include <type_traits>  // is_*
+--- build2-toolchain-0.16.0/build.sh.orig	2024-01-16 14:51:24.342555945 +0100
++++ build2-toolchain-0.16.0/build.sh	2024-01-16 15:31:07.822696709 +0100
+@@ -308,8 +308,8 @@
+ 
+ # Compile and link options.
+ #
+-compile_ops=
+-link_ops=
++compile_ops="-O3 -latomic"
++link_ops=-latomic
+ 
+ while test $# -ne 0; do
+   if test "$1" != "--"; then
+@@ -606,9 +606,9 @@
+ #
+ run cd build2
+ if test -z "$make"; then
+-  run ./bootstrap.sh "$cxx" -w
++  run ./bootstrap.sh "$cxx" -w -latomic
+ else
+-  run $make -f ./bootstrap.gmake "CXX=$cxx" CXXFLAGS=-w
++  run $make -f ./bootstrap.gmake "CXX=$cxx" CXXFLAGS='-w -latomic'
+ fi
+ run build2/b-boot --version
+ 
+--- build2-toolchain-0.16.0/libbutl/libbutl/buildfile.orig	2024-01-17 09:16:20.994868370 +0100
++++ build2-toolchain-0.16.0/libbutl/libbutl/buildfile	2024-01-17 09:16:35.177406211 +0100
+@@ -76,7 +76,7 @@
+ }
+ 
+ if! $windows
+-  cxx.libs += -lpthread
++  cxx.libs += -lpthread -latomic
+ 
+ # Include the generated version header into the distribution (so that we don't
+ # pick up an installed one) and don't remove it when cleaning in src (so that