Fix a couple gdb.dwarf2/ testcases with "clang -flto"

gdb.dwarf2/atomic-type.exp and gdb.dwarf2/ada-linkage-name.exp fail
when testing with "clang -flto" as compiler, like:

 $ make check TESTS="gdb.dwarf2/ada-linkage-name.exp" RUNTESTFLAGS="CC_FOR_TARGET='clang -flto'"

because with -flto, functions that aren't referenced anywhere are not
emitted in the final binary.  Fix it by adding uses of the functions.

gdb/testsuite/ChangeLog:

	* gdb.dwarf2/ada-linkage-name.c (main): Move to the bottom of the
	file and add calls to first and second.
	* gdb.dwarf2/atomic.c (main): Move to the bottom of the file and
	add call to f.

1 files changed, 11 insertions, 7 deletions

diff --git a/gdb/testsuite/gdb.dwarf2/ada-linkage-name.c b/gdb/testsuite/gdb.dwarf2/ada-linkage-name.c
index adcb009..fe04147 100644
--- a/gdb/testsuite/gdb.dwarf2/ada-linkage-name.c
+++ b/gdb/testsuite/gdb.dwarf2/ada-linkage-name.c
@@ -15,13 +15,6 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-int
-main (void)
-{
-  asm ("main_label: .globl main_label");
-  return 0;
-}
-
 /* First dummy function.  */
 
 int
@@ -39,3 +32,14 @@ second (char *x)
   asm ("second_label: .globl second_label");
   return 0;
 }
+
+
+int
+main (void)
+{
+  asm ("main_label: .globl main_label");
+
+  first (0);
+  second (0);
+  return 0;
+}