requirements: +bzip2, +zstd

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74396 15284696-431f-4ddb-bdfa-cd5b030d7da7

REQUIREMENTS.html

@@ -62,7 +62,7 @@ map formats<br>
 
 </ul>
 
-<h3>Optional requirements:</h3>
+<h3>Optional packages:</h3>
 
 Note: also the respective development packages (commonly named xxx-dev or xxx-devel) need
 to be installed.
@@ -73,6 +73,14 @@ to be installed.
 gcc: <a href="http://www.gnu.org/software/gcc/gcc.html">http://www.gnu.org/software/gcc/gcc.html</a>
 </li>
 
+<li><b>bzip2</b>, needed for raster compression with bzip2<br>
+<a href="http://www.bzip.org">http://www.bzip.org</a>
+</li>
+
+<li><b>zstd</b> (Zstandard), needed for raster compression with zstd<br>
+<a href="https://facebook.github.io/zstd">https://facebook.github.io/zstd</a>
+</li>
+
 <li><b>FFTW 2.x or 3.x</b> (library for computing the Discrete Fourier Transform), required
 for i.fft and i.ifft and other modules<br>
 <a href="http://www.fftw.org">http://www.fftw.org</a>