Macro-driven conditional compilation was a chaos.

New scheme is:

contrib/fuse-lib/mount-common.c:
  libfuse routines used both by glusterfs and fusermount
contrib/fuse-lib/mount.c:
  libfuse-derived but customized mounting code for glusterfs
contrib/fuse-util/mount_util.c:
  libfuse routines used only by fusermount

Change-Id: I3e0ba7f74e36556b78244cd7676eb4d379939602
BUG: 762389
Signed-off-by: Csaba Henk <csaba@redhat.com>
Reviewed-on: http://review.gluster.com/3342
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

Following commits were ported (commit ids as of
http://git.gluster.com/?p=users/csaba/fuse.git
repo):

commit 06fe3eb9c864b69bea98600c0a7eab7b63834735
Author: mszeredi <mszeredi>
Date:   Thu Feb 18 11:05:12 2010 +0000

    * Fix stack alignment for clone()

 ChangeLog               |    4 ++++
 include/fuse_lowlevel.h |    1 +
 util/fusermount.c       |    9 ++++-----
 3 files changed, 9 insertions(+), 5 deletions(-)

commit dfe1aab6520d70d72d36edf0508fef9a865daa5f
Author: mszeredi <mszeredi>
Date:   Tue Jan 26 18:20:12 2010 +0000

    * Fix race if two "fusermount -u" instances are run in parallel.
    Reported by Dan Rosenberg

    * Make sure that the path to be unmounted doesn't refer to a
    symlink

 ChangeLog         |    8 +
 lib/mount.c       |    2 +-
 lib/mount_util.c  |   31 +++--
 lib/mount_util.h  |    3 +-
 util/fusermount.c |  380 +++++++++++++++++++++++++++++++++++++++++++++--------
 5 files changed, 351 insertions(+), 73 deletions(-)

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 657 (Metabug for tracking fuse upstream)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=657