In the process of compiling aircrack-ng from source, I hit a lot of errors mostly to do with a variable called -Werror. This is what you need to do to compile aircrack-ng without the pesky errors.
sudo apt-get install build-essential
sudo apt-get install libssl-dev
tar -zxvf aircrack-ng-1.1.tar.gz
In the aircrack-ng-1.1 directory there is a file called common.mak, use your favorite editor to open the file and scroll down till you see the following line:
CFLAGS ?= -g -W -Wall -Werror -O3
Delete the -Werror variable, so that the line now looks like the following. Save and exit.
CFLAGS ?= -g -W -Wall -O3
Run make and make install to get aircrack-ng up and running.