Cross-compile C application for Win32/64 on Ubuntu

I used the MingW libraries to compile an application written in C (with makefile etc.)  with Ubuntu-32bit as host and Win 32/64 as the target.

Installation
sudo apt-get install mingw32 (for libraries with win32 as target ?)
sudo apt-get install mingw64 (for libraries with win64 as target ?)

Compilation
  i686-w64-mingw32-gcc      -o target.exe main.c // Compile for win32 target.
  x86_64-w64-mingw32-gcc -o target.exe main.c // Compile for win64 target.

Since my application used makefile,  I changed the variable
CC = x86_64-w64-mingw32-gcc (previously CC = gcc)

Tips 
The application I was working on had a subdirectory with a bunch of c files and a makefile to compile them. Sort of a library. My first mistake was that I hadn't removed *.o files from that directory, which means compilation of appln. was showing a ton of linker errors. So I removed the *.o, *.exe from all the folders. Then I changed the gcc command in this folder's makefile, so this library could be recompiled again with this application.

Other than Ubuntu, I tried to compile this appln. using MinGW32 tools for Win7. I could get it to work to compile and install simple applications, but couldn't get mine to work. The reason was that my application compilation requires bison / flex libraries and I couldn't get it to work on MinGW32 tools for win7.

References
http://wiki.wxwidgets.org/Cross-Compiling_Under_Linux
http://www.mingw.org/wiki/MinGW_for_First_Time_Users_HOWTO
http://wiki.wxwidgets.org/Cross-Compiling_Under_Linux
http://mingw-w64.sourceforge.net/download.php#automated-builds

Install Thinkpad tools on Ubuntu 12.04

I own a T400 for 51/2 years now, and it has been treating me very well. I haven't still replaced my original battery, it still holds up 90% of its original capacity. Great Job Lenovo ! One possible reason is that I am using Battery Thresholding since the first few weeks of buying this machine, and made sure that this Thresholding works on all the OS I use. I use Ubuntu around 95% of my time using my PC (lets not talk about the other 5% time I spend editing the Word / PPTs on the crappy OS).  Thinkpad provides Battery driver software for Windows, but doesn't provide any drivers for Linux. Luckily drivers exist, and I found it on this link

The installation steps are very easy, I am reproducing here from the above link.

1. sudo apt-get install tp-smapi-dkms
2. sudo modprobe tp-smapi
3. Verify that the module is installed, using lsmod | grep smapi
4. Enable the superuser (su) mode on the terminal and do
echo 30 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
echo 80 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh

5. Make sure that the module loads on startup. Add the following line in /etc/modules

tp_smapi

6. To set the threshold settings at startup, Add the following lines in the tail of /etc/sysfs.conf  file

devices/platform/smapi/BAT0/start_charge_thresh = 50

devices/platform/smapi/BAT0/stop_charge_thresh = 80

EOF

Thats it. I focused only on battery thresholding, but there are many other tools that this module provides. Just check the files in /sys/devices/platform/smapi/BAT0/*