Clean up documentation around gnutls and C++-11

2 files changed, 36 insertions, 8 deletions

diff --git a/README.md b/README.md
index 2356decb..96b3ace9 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,9 @@ QPDF requires a C++ compiler that supports C++-11.
 
 QPDF depends on the external libraries [zlib](http://www.zlib.net/) and [jpeg](http://www.ijg.org/files/). The [libjpeg-turbo](https://libjpeg-turbo.org/) library is also known to work since it is compatible with the regular jpeg library, and QPDF doesn't use any interfaces that aren't present in the straight jpeg8 API. These are part of every Linux distribution and are readily available. Download information appears in the documentation. For Windows, you can download pre-built binary versions of these libraries for some compilers; see [README-windows.md](README-windows.md) for additional details.
 
-If the optional gnutls crypto provider is enabled, then gnutls is also required. This is discussed more in `Crypto providers` below.
+If the optional gnutls crypto provider is enabled,
+then [gnutls](https://www.gnutls.org/) is also required. This is
+discussed more in `Crypto providers` below.
 
 # Licensing terms of embedded software
 
diff --git a/manual/qpdf-manual.xml b/manual/qpdf-manual.xml
index 24747159..9e0d6533 100644
--- a/manual/qpdf-manual.xml
+++ b/manual/qpdf-manual.xml
@@ -118,6 +118,11 @@
     <itemizedlist>
      <listitem>
       <para>
+       A C++ compiler that supports C++-11.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
        zlib: <ulink url="http://www.zlib.net/">http://www.zlib.net/</ulink>
       </para>
      </listitem>
@@ -131,6 +136,13 @@
      </listitem>
      <listitem>
       <para>
+       <emphasis>Recommended but not required:</emphasis> gnutls:
+       <ulink url="https://www.gnutls.org/">https://www.gnutls.org/</ulink>
+       to be able to use the gnutls crypto provider
+      </para>
+     </listitem>
+     <listitem>
+      <para>
        gnu make 3.81 or newer: <ulink url="http://www.gnu.org/software/make">http://www.gnu.org/software/make</ulink>
       </para>
      </listitem>
@@ -151,13 +163,6 @@
        -u</command>.
       </para>
      </listitem>
-     <listitem>
-      <para>
-       A C++ compiler that works well with STL and has the <type>long
-       long</type> type. Most modern C++ compilers should fit the bill
-       fine. QPDF is tested with gcc, clang, and Microsoft Visual C++.
-      </para>
-     </listitem>
     </itemizedlist>
    </para>
    <para>
@@ -4625,6 +4630,27 @@ print "\n";
      <itemizedlist>
       <listitem>
        <para>
+        Build Changes
+       </para>
+       <itemizedlist>
+        <listitem>
+         <para>
+          A C++-11 compiler is now required to build qpdf.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          A new crypto provider that uses gnutls for crypto functions
+          is now available and can be enabled at build time. See <xref
+          linkend="ref.crypto"/> for more information about crypto
+          providers and <xref linkend="ref.crypto.build"/> for
+          specific information about the build.
+         </para>
+        </listitem>
+       </itemizedlist>
+      </listitem>
+      <listitem>
+       <para>
         Library Enhancements
        </para>
        <itemizedlist>