configure.ac: Define booleans to 1 when set, instead of an empty string

This makes the generated config.h look a lot nicer.

diff --git a/configure.ac b/configure.ac
index bd1f006..1e48ab3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -30,7 +30,7 @@ AC_PROG_CC
 AC_PROG_LIBTOOL
 AC_C_INLINE
 AM_PROG_CC_C_O
-AC_DEFINE([_GNU_SOURCE], [], [Use GNU extensions])
+AC_DEFINE([_GNU_SOURCE], 1, [Use GNU extensions])
 
 AM_MAINTAINER_MODE
 
@@ -38,7 +38,7 @@ AC_MSG_CHECKING([operating system])
 PC_LIBS_PRIVATE=
 case $host in
 *-linux*)
-       AC_DEFINE(OS_LINUX, [], [Linux backend])
+       AC_DEFINE(OS_LINUX, 1, [Linux backend])
        AC_SUBST(OS_LINUX)
        AC_MSG_RESULT([Linux])
        backend="linux"
@@ -50,7 +50,7 @@ case $host in
        AC_DEFINE([POLL_NFDS_TYPE],[nfds_t],[type of second poll() argument])
        ;;
 *-darwin*)
-       AC_DEFINE(OS_DARWIN, [], [Darwin backend])
+       AC_DEFINE(OS_DARWIN, 1, [Darwin backend])
        AC_SUBST(OS_DARWIN)
        AC_MSG_RESULT([Darwin/Mac OS X])
        backend="darwin"
@@ -63,7 +63,7 @@ case $host in
                [#include <poll.h>])
 ;;
 *-mingw*)
-       AC_DEFINE(OS_WINDOWS, [], [Windows backend])
+       AC_DEFINE(OS_WINDOWS, 1, [Windows backend])
        AC_SUBST(OS_WINDOWS)
        AC_MSG_RESULT([Windows])
        backend="windows"
@@ -73,7 +73,7 @@ case $host in
        AC_DEFINE([POLL_NFDS_TYPE],[unsigned int],[type of second poll() argument])
        ;;
 *-cygwin*)
-       AC_DEFINE(OS_WINDOWS, [], [Windows backend])
+       AC_DEFINE(OS_WINDOWS, 1, [Windows backend])
        AC_SUBST(OS_WINDOWS)
        AC_MSG_RESULT([Cygwin (using Windows backend)])
        backend="windows"
@@ -119,7 +119,7 @@ if test "x$use_timerfd" = "xno"; then
 else
        if test "x$timerfd_h" = "x1" -a "x$tfd_hdr_ok" = "xyes"; then
                AC_MSG_RESULT([yes])
-               AC_DEFINE(USBI_TIMERFD_AVAILABLE, [], [timerfd headers available])
+               AC_DEFINE(USBI_TIMERFD_AVAILABLE, 1, [timerfd headers available])
        else
                AC_MSG_RESULT([no (header not available)])
        fi