[clutter] configure: Don't declare functions in AC_TRY_LINK and AC_TRY_COMPILE

[Ting-Wei Lan <lantw src gnome org>]

commit 7a46910bc92b06f0a8d8016e142c605c3fe8538a
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sat Jan 20 17:30:57 2018 +0800

    configure: Don't declare functions in AC_TRY_LINK and AC_TRY_COMPILE
    
    https://bugzilla.gnome.org/show_bug.cgi?id=792716

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4ec5a9a..4257498 100644
--- a/configure.ac
+++ b/configure.ac
@@ -160,7 +160,7 @@ AC_ARG_ENABLE([Bsymbolic],
                 saved_LDFLAGS="${LDFLAGS}"
                 AC_MSG_CHECKING([for -Bsymbolic-functions linker flag])
                 LDFLAGS=-Wl,-Bsymbolic-functions
-                AC_TRY_LINK([], [int main (void) { return 0; }],
+                AC_TRY_LINK([], [return 0],
                             [
                               AC_MSG_RESULT([yes])
                               enable_Bsymbolic=yes
@@ -189,7 +189,7 @@ case "$host" in
     SAVED_CFLAGS="${CFLAGS}"
     CFLAGS="-fvisibility=hidden"
     AC_MSG_CHECKING([for -fvisibility=hidden compiler flag])
-    AC_TRY_COMPILE([], [int main (void) { return 0; }],
+    AC_TRY_COMPILE([], [return 0],
                    AC_MSG_RESULT(yes)
                    enable_fvisibility_hidden=yes,
                    AC_MSG_RESULT(no)