$(..) is not portable -> use `...`

[[Imported from SVN: r4731]]

m4/dune_all.m4

@@ -180,7 +180,7 @@ AC_DEFUN([DUNE_CHECK_ALL_M],[
     AC_HELP_STRING([--with-hostid=HOST_IDENTIFIER],
                  [host identifier used for automated test runs]))
   if test "x$with_hostid" = "xno" ; then 
-    with_hostid="$ac_hostname ($(uname -sm), $COMPILER_NAME)";
+    with_hostid="$ac_hostname (`uname -sm`, $COMPILER_NAME)";
   fi
   AC_SUBST(host, $with_hostid)
   AC_ARG_WITH(tag,

m4/dune_compiler.m4

@@ -43,7 +43,7 @@ if test "x$compilercheck" != "xyes" ; then
   AC_MSG_WARN([compilercheck is disabled. DANGEROUS!])    
 else
   if $CXX conftest.cc -o conftest.$ac_exeext >&5; then
-	COMPILER_NAME=$(./conftest.$ac_exeext)
+	COMPILER_NAME=`./conftest.$ac_exeext`
     rm -f conftest.$ac_exeext
   else
     AC_MSG_ERROR([Your compiler is not officially supported by dune

m4/f5.m4

@@ -32,7 +32,7 @@ AC_DEFUN([DUNE_PATH_F5],[
    echo -n "checking for make/arch... "
    if test -x $F5ARCH ; then
      echo "yes"
-     LDFLAGS="$HDF5_LDFLAGS -L$with_f5/lib/$($F5ARCH)"
+     LDFLAGS="$HDF5_LDFLAGS -L$with_f5/lib/`$F5ARCH`"
      F5_LDFLAGS="$LDFLAGS"
      CPPFLAGS="$CPPFLAGS -I$with_f5"
    else