Install ROS hydro from source

edit

It seems that ros hydro has some problems installing from source to Ubuntu 12.04 as indicated in ( http://wiki.ros.org/hydro/Installatio... )

The following packages have unmet dependencies:
libpcl-1.7-all-dev : Depends: libpcl-apps-1.7-dev but it is not going to be installed
Depends: libpcl-io-1.7-dev but it is not going to be installed
Depends: libpcl-outofcore-1.7-dev but it is not going to be installed
Depends: libpcl-people-1.7-dev but it is not going to be installed
Depends: libpcl-recognition-1.7-dev but it is not going to be installed
Depends: libpcl-visualization-1.7-dev but it is not going to be installed
libpcl-1.7-bin : Depends: libpcl-io-1.7 but it is not going to be installed
Depends: libpcl-visualization-1.7 but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

After these errors, I tried to install libpcl by using $sudo apt-get install libpcl-all-dev, but there were other unmet dependencies...

When ROS hydro compile from source, it seems that Gazebo cannot be compiled.

CMake Error at /home/meng/ros_catkin_ws/install_isolated/share/catkin/cmake/catkin_package.cmake:159 (message):
catkin_package() DEPENDS on 'gazebo' which must be find_package()-ed
before. If it is a catkin package it can be declared as CATKIN_DEPENDS
instead without find_package()-ing it.
Call Stack (most recent call first):
/home/meng/ros_catkin_ws/install_isolated/share/catkin/cmake/catkin_package.cmake:98 (_catkin_package)
CMakeLists.txt:72 (catkin_package)

-- Configuring incomplete, errors occurred!
<== Failed to process package 'gazebo_plugins':
Command '/home/meng/ros_catkin_ws/install_isolated/env.sh cmake /home/meng/ros_catkin_ws/src/gazebo_ros_pkgs/gazebo_plugins -DCATKIN_DEVEL_PREFIX=/home/meng/ros_catkin_ws/devel_isolated/gazebo_plugins -DCMAKE_INSTALL_PREFIX=/home/meng/ros_catkin_ws/install_isolated -DCMAKE_BUILD_TYPE=Release' returned non-zero exit status 1

Reproduce this error by running:
==> cd /home/meng/ros_catkin_ws/build_isolated/gazebo_plugins && /home/meng/ros_catkin_ws/install_isolated/env.sh cmake /home/meng/ros_catkin_ws/src/gazebo_ros_pkgs/gazebo_plugins -DCATKIN_DEVEL_PREFIX=/home/meng/ros_catkin_ws/devel_isolated/gazebo_plugins -DCMAKE_INSTALL_PREFIX=/home/meng/ros_catkin_ws/install_isolated -DCMAKE_BUILD_TYPE=Release

Command failed, exiting.

Could someone provide some suggestions? Thanks a lot! :)