extra/libunwind: v5 fix

extra/libunwind/PKGBUILD

@@ -6,6 +6,7 @@
 
 # ALARM: Kevin Mihelich <kevin@archlinuxarm.org>
 #  - aarch64 support patch
+#  - build v5 with system libatomic_ops
 
 pkgname=libunwind
 pkgver=1.1
@@ -15,6 +16,7 @@ arch=('i686' 'x86_64')
 url='http://www.nongnu.org/libunwind/'
 license=('GPL')
 depends=('glibc' 'xz')
+depends_arm=('libatomic_ops')
 source=("http://download.savannah.gnu.org/releases/$pkgname/$pkgname-$pkgver.tar.gz"
         '001-invalid-dwarf-opcodes-can-cause-references-beyond.patch'
         'libunwind-aarch64.patch')
@@ -32,6 +34,9 @@ prepare() {
 
 build() {
   cd $pkgname-$pkgver
+
+  [[ $CARCH == "arm" ]] && LDFLAGS+=" -latomic_ops" && CFLAGS+=" -DAO_USE_PTHREAD_DEFS=1"
+
   ./configure CFLAGS="$CFLAGS -U_FORTIFY_SOURCE" --prefix=/usr
   make
 }