Merge pull request #3250 from ffontaine/master

fix static build with libatomic

RELICENSE/FabriceFontaine.md

+# Permission to Relicense under MPLv2 or any other OSI approved license chosen by the current ZeroMQ BDFL
+
+This is a statement by Fabrice Fontaine
+that grants permission to relicense its copyrights in the libzmq C++
+library (ZeroMQ) under the Mozilla Public License v2 (MPLv2) or any other
+Open Source Initiative approved license chosen by the current ZeroMQ
+BDFL (Benevolent Dictator for Life).
+
+A portion of the commits made by the Github handle "ffontaine", with
+commit author "Fabrice Fontaine <fontaine.fabrice@gmail.com>", are copyright of Fabrice Fontaine.
+This document hereby grants the libzmq project team to relicense libzmq,
+including all past, present and future contributions of the author listed above.
+
+Fabrice Fontaine
+2018-09-13

acinclude.m4

@@ -680,8 +680,8 @@ int main (int, char **)
     [AC_MSG_RESULT(yes) ; GCC_ATOMIC_BUILTINS_SUPPORTED=1 libzmq_cv_has_atomic_instrisics="yes" ; $1])
 
     if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" != x1; then
-        save_LDFLAGS=$LDFLAGS
-        LDFLAGS="$LDFLAGS -latomic"
+        save_LIBS=$LIBS
+        LIBS="$LIBS -latomic"
         AC_LINK_IFELSE([AC_LANG_SOURCE([
         /* atomic intrinsics test */
         int v = 0;
@@ -691,9 +691,8 @@ int main (int, char **)
             return t;
         }
         ])],
-        [AC_MSG_RESULT(yes) ; libzmq_cv_has_atomic_instrisics="yes" LIBS="-latomic" ; $1],
-        [AC_MSG_RESULT(no) ; libzmq_cv_has_atomic_instrisics="no"; $2])
-        LDFLAGS=$save_LDFLAGS
+        [AC_MSG_RESULT(yes) ; libzmq_cv_has_atomic_instrisics="yes" ; $1],
+        [AC_MSG_RESULT(no) ; libzmq_cv_has_atomic_instrisics="no" LIBS=$save_LIBS ; $2])
     fi
 }])