gistfile1.txt

-- Commands --
As root:
pacman -Syu
pacman -S git curl
pacman -S base-devel
adduser blah (etc.)

As blah:
bash < <(curl -s https://raw.github.com/wayneeseguin/rvm/master/binscripts/rvm-installer )
echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function' >> ~/.bash_profile
rvm requirements

As root:
pacman -Sy --noconfirm gcc patch curl zlib readline libxml2 libxslt git autoconf diffutils make libtool bison subversion

As blah:
rvm install 1.8.7-p330

-- Output --
$ rvm install 1.8.7-p330
...
ruby-1.8.7-p330 - #extracting ruby-1.8.7-p330 to /home/blah/.rvm/src/ruby-1.8.7-p330
ruby-1.8.7-p330 - #extracted to /home/blah/.rvm/src/ruby-1.8.7-p330
Applying patch 'stdout-rouge-fix' (located at /home/blah/.rvm/patches/ruby/1.8.7/stdout-rouge-fix.patch)
Applying patch 'no_sslv2' (located at /home/blah/.rvm/patches/ruby/1.8.7/no_sslv2.diff)
ruby-1.8.7-p330 - #configuring 
ruby-1.8.7-p330 - #compiling 

-- Tailing make.log --
make[1]: Leaving directory `/home/blah/.rvm/src/ruby-1.8.7-p330/ext/zlib'
making ruby
make[1]: Entering directory `/home/blah/.rvm/src/ruby-1.8.7-p330'
gcc -g -O2  -fPIC    -DRUBY_EXPORT -D_GNU_SOURCE=1  -L.  -rdynamic -Wl,-export-dynamic   main.o  -Wl,-R -Wl,/home/blah/.rvm/rubies/ruby-1.8.7-p330/lib -L/home/blah/.rvm/rubies/ruby-1.8.7-p330/lib -lruby -lrt -ldl -lcrypt -lm   -o ruby
make[1]: Leaving directory `/home/blah/.rvm/src/ruby-1.8.7-p330'