Fix configure and build errors on OS X Yosemite: Substitute preadv an…

…d pwritev with lseek+readv/writev if not available. Redundant check for clock_gettime removed, which was already checked in the platform case statement and failed on darwin systems.

Signed-off-by: Clemens Gruber <clemensgru@gmail.com>

configure.ac

@@ -461,14 +461,6 @@ AC_DEFINE_UNQUOTED([DBUS_CLIENT_GROUP], ["${DBUS_CLIENT_GROUP}"], [DBus client g
 AC_MSG_RESULT(${DBUS_CLIENT_GROUP})
 AC_SUBST([DBUS_CLIENT_GROUP])
 
-dnl Check for clock_gettime.  Some systems put it into -lc, while
-dnl others use -lrt.  Try the first and fallback to the latter.
-RT_LIB=
-AC_CHECK_FUNC([clock_gettime], [:],
-              [AC_CHECK_LIB([rt], [clock_gettime], [RT_LIB="-lrt"],
-                            [AC_MSG_ERROR([Your system lacks clock_gettime])])])
-AC_SUBST(RT_LIB)
-
 PKG_CHECK_MODULES([LIBEVENT], [libevent >= 2.0])
 
 have_dbus=false

src/util.c

@@ -290,7 +290,12 @@ int file_write(int fd, void *buf, size_t sz)
 	ssize_t ret;
 	iov[0].iov_base = buf;
 	iov[0].iov_len = sz;
+#ifdef HAVE_PWRITEV
 	ret = IGNORE_EINTR (pwritev (fd, iov, 1, 0));
+#else
+	lseek (fd, 0, SEEK_SET);
+	ret = IGNORE_EINTR (writev (fd, iov, 1));
+#endif
 	if (ret != sz)
 	{
 		return -1;
@@ -332,7 +337,12 @@ int file_read(int fd, void *buf, size_t sz)
 	struct iovec iov[1];
 	iov[0].iov_base = buf;
 	iov[0].iov_len = sz;
+#ifdef HAVE_PREADV
 	if (preadv (fd, iov, 1, 0) != sz)
+#else
+	lseek (fd, 0, SEEK_SET);
+	if (readv (fd, iov, 1) != sz)
+#endif
 	{
 		/* Returns -1 on read failure */
 		return -1;