Building R for the Raspberry

[llrs]

Many thanks for providing this resource for the R community.
I just started using a Raspberry Pi and I want to use R in it for some tasks.

I see that the buildr and the buildreleases have almost the same code.
The only difference are these:

51c51
<     prefix = "--prefix=/opt/R/{}".format(version_no)
---
>     prefix = "--prefix=/opt/R/release"
60c60,61
<         "--with-x"
---
>         "--with-x",
>         "CXXPICFLAGS=-fPIC",

Which one is used to build R? The scripts do not seem to be doing anything special, are they only building from the source code and then packages in a appropriate manner (.deb)?