Use a single WS_NORETURN macro

Having to define two macros for marking a function as never returning
seems a bit redundant. Merge the MSVC and GCC-like attributes into a
single WS_NORETURN.

Tested with Clang 3.7.1, GCC 4.4.7 and even GCC 4.1.2 using this small
program (-Wall -Wextra, the first two generate warnings for
uninitialized variables, the last one compiles without warnings):

    #include <stdlib.h>
    __attribute__((noreturn)) void foo() { exit(1); }
    __attribute__((noreturn)) void bar();
    void bar() { exit(1); }
    int main() {
      int j, i;
      if (i) { bar(); return j; }
      foo();
      return j;
    }

Change-Id: I7d19c15e61b8f8fa4936864407199c4109f8cc82
Reviewed-on: https://code.wireshark.org/review/14822
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

1 files changed, 2 insertions, 11 deletions

diff --git a/configure.ac b/configure.ac
index 272af90a7b..50f6c85ff8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1221,8 +1221,10 @@ AC_SUBST(CFLAGS_SSE42)
 #
 if test "x$GCC" = "xyes" -o "x$CC" = "xclang" ; then
   AC_DEFINE(_U_, __attribute__((unused)), [Hint to the compiler that a function parameters is not used])
+  AC_DEFINE(WS_NORETURN, __attribute((noreturn)), [Hint to the compiler that a function never returns])
 else
   AC_DEFINE(_U_, , [Hint to the compiler that a function parameters is not used])
+  AC_DEFINE(WS_NORETURN, , [Hint to the compiler that a function never returns])
 fi
 
 # If we're running GCC or CLang, use FORTIFY_SOURCE=2
@@ -2651,17 +2653,6 @@ else
 fi
 AC_SUBST(LIBSSH_LIBS)
 
-#
-# Define WS_MSVC_NORETURN appropriately for declarations of routines that
-# never return (just like Charlie on the MTA).
-#
-# Note that MSVC++ expects __declspec(noreturn) to precede the function
-# name and GCC, as far as I know, expects __attribute__((noreturn)) to
-# follow the function name, so we need two different flavors of
-# noreturn tag.
-#
-AC_DEFINE(WS_MSVC_NORETURN,, [Define as the string to precede declarations of routines that never return])
-
 dnl Checks for typedefs, structures, and compiler characteristics.
 # AC_C_CONST