util: build with external libatomic

Recent versions of gcc on some architectures (MIPS, PPC, ...) moved
atomic functions into a separate library. As we are using atomic
load/store in util/time.c we may need to link libgnunetutil against
libatomic for __atomic_load_8 and __atomic_store_8 to be defined.

Fixes build problem on MIPS:
ld: ./.libs/libgnunetutil.so: undefined reference to `__atomic_store_8'
ld: ./.libs/libgnunetutil.so: undefined reference to `__atomic_load_8'
collect2: error: ld returned 1 exit status

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 0ba06f4bb..5fa6e907e 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -123,6 +123,12 @@ libgnunetutil_la_SOURCES = \
   speedup.c speedup.h \
         proc_compat.c
 
+if HAVE_LIBATOMIC
+  LIBATOMIC= -latomic
+else
+  LIBATOMIC=
+endif
+
 if HAVE_LIBIDN
   LIBIDN= -lidn
 else
@@ -137,6 +143,7 @@ endif
 
 libgnunetutil_la_LIBADD = \
   $(GCLIBADD) $(WINLIB) \
+  $(LIBATOMIC) \
   $(LIBGCRYPT_LIBS) \
   $(LTLIBICONV) \
   $(LTLIBINTL) \