[libsoup] configure: Don't declare functions in AC_TRY_COMPILE

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

commit d3abf0cc20a75c17680b85bcb4d9b684c2a756b4
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sat Jan 20 17:24:29 2018 +0800

    configure: Don't declare functions in AC_TRY_COMPILE
    
    https://bugzilla.gnome.org/show_bug.cgi?id=792715

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 9fbf182..eb5ad55 100644
--- a/configure.ac
+++ b/configure.ac
@@ -377,7 +377,7 @@ 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)