added valgrind suppressions file

ecm.supp

+# This is a suppression file for valgrind
+
+# In order to generate it, re-run valgrind as follows:
+# valgrind --leak-check=full --gen-suppressions=all --log-file=ecm.supp ./my_program arg1 # arg2 ...
+
+# The "..." joker matches several possible lines in the call trace.
+
+
+{
+   copyi_false_positive
+   Memcheck:Addr8
+   fun:__gmpn_copyi
+   obj:/usr/lib/x86_64-linux-gnu/libgmp.so.10.5.0
+   fun:__gmpn_mul_fft
+   fun:__ecm_mpres_mul_z_to_z
+   fun:pm1_sequence_g
+   fun:__ecm_pm1fs2_ntt
+   fun:pm1
+   fun:ecm_factor
+   fun:main
+}

m4/valgrind-tests.m4

@@ -11,7 +11,7 @@ AC_DEFUN([gl_VALGRIND_TESTS],
   if test "$opt_valgrind_tests" = "yes" && test "$cross_compiling" = no; then
     AC_CHECK_PROGS(VALGRIND, valgrind)
   fi
-  OPTS="-q --error-exitcode=1 --leak-check=full"
+  OPTS="-q --error-exitcode=1 --leak-check=full --suppressions=ecm.supp"
   if test -n "$VALGRIND" \
      && $VALGRIND $OPTS $SHELL -c 'exit 0' > /dev/null 2>&1; then
     opt_valgrind_tests=yes