fftw: add details of how to build the alternative libfftw3f

git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@19023 af4574ff-66df-0310-9fd7-8a98e5e911e0

general/genlib/fftw.xml

@@ -112,6 +112,17 @@ make</userinput></screen>
         <ulink url="http://gmic.eu/">G'MIC</ulink>.
       </para>
 
+      <para>
+        <option>--enable-float</option>: This enables floating point, and
+        will cause the library to be called <filename
+        class="libraryfile">libfftw3f.so</filename> (needed by <ulink
+        url="http://www.rawtherapee.com/">RawTherapee</ulink> (and similarly
+        for the threaded library if that is built (not needed by RawTherapee).
+        These versions are not usable by packages in this book which use <filename
+        class="libraryfile">libfftw3</filename> so if you need both you will
+        need to build <application>fftw</application> twice.
+      </para>
+
   </sect2>
 
   <sect2 role="content">
@@ -127,7 +138,8 @@ make</userinput></screen>
           fftw-wisdom and fftw-wisdom-to-conf
         </seg>
         <seg>
-          libfftw3.so and libfftw3_threads.so
+          libfftw3.so and libfftw3_threads.so, or libfftw3f.so and
+          libfftw3f_threads.so
         </seg>
         <seg>
           None
@@ -168,6 +180,54 @@ make</userinput></screen>
         </listitem>
       </varlistentry>
 
+      <varlistentry id="libfftw3">
+        <term><filename class="libraryfile">libfftw3.so</filename></term>
+        <listitem>
+          <para>
+            is the Fast Fourier Transform library
+          </para>
+          <indexterm zone="fftw libfftw3">
+            <primary sortas="c-libfftw3">libfftw3.so</primary>
+          </indexterm>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry id="libfftw3_threads">
+        <term><filename class="libraryfile">libfftw3_threads.so</filename></term>
+        <listitem>
+          <para>
+            is the threaded Fast Fourier Transform library
+          </para>
+          <indexterm zone="fftw libfftw3_threads">
+            <primary sortas="c-libfftw3_threads">libfftw3_threads.so</primary>
+          </indexterm>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry id="libfftw3f">
+        <term><filename class="libraryfile">libfftw3f.so</filename></term>
+        <listitem>
+          <para>
+            is the floating-point Fast Fourier Transform library
+          </para>
+          <indexterm zone="fftw libfftw3f">
+            <primary sortas="c-libfftw3f">libfftw3f.so</primary>
+          </indexterm>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry id="libfftw3f_threads">
+        <term><filename class="libraryfile">libfftw3f_threads.so</filename></term>
+        <listitem>
+          <para>
+            is the threaded floating-point Fast Fourier Transform library
+          </para>
+          <indexterm zone="fftw libfftw3f_threads">
+            <primary sortas="c-libfftw3f_threads">libfftw3f_threads.so</primary>
+          </indexterm>
+        </listitem>
+      </varlistentry>
+
     </variablelist>
 
   </sect2>

introduction/welcome/changelog.xml

@@ -45,6 +45,11 @@
     <listitem>
       <para>August 15th, 2017</para>
       <itemizedlist>
+        <listitem>
+          <para>[ken] - Add optional instructions to fftw for installing the
+          threaded libfftw3f lib(s) (needs a separate build from the regular
+          fftw build).</para>
+        </listitem>
         <listitem>
           <para>[pierre] - Update to GCC and GCC-Ada 7.2.0. Fixes
           <ulink url="&blfs-ticket-root;9612">#9612</ulink>.</para>