Add instructions for pie and ssp in clang

Just instructions for now because in a hurry... TODO:
- Add command explanations
- Update changelog
- also gcc in blfs needs to get the switches for default pie and
  default ssp

general/prog/llvm.xml

@@ -148,6 +148,15 @@
         </listitem>
       </itemizedlist>
 
+      <itemizedlist spacing="compact">
+        <listitem>
+          <para>
+            SSP patch:
+            <ulink url="&patch-root;/clang-&llvm-version;-enable_default_ssp-1.patch"/>
+          </para>
+        </listitem>
+      </itemizedlist>
+
     <bridgehead renderas="sect3">LLVM Dependencies</bridgehead>
 
     <bridgehead renderas="sect4">Required</bridgehead>
@@ -226,6 +235,7 @@ mv projects/compiler-rt-&llvm-version;.src projects/compiler-rt</userinput></scr
 <!-- need <../<patch> instead of -i because -d changes directory
      before applying -i -->
 <screen><userinput remap="pre">patch -Np2 -d projects/compiler-rt &lt;../compiler-rt-14.0.6-glibc_2_36-1.patch</userinput></screen>
+<screen><userinput remap="pre">patch -Np2 -d tools/clang &lt;../clang-&llvm-version;-enable_default_ssp-1.patch</userinput></screen>
 
     <para>
       Install <application>LLVM</application> by running the following
@@ -245,6 +255,7 @@ cmake -DCMAKE_INSTALL_PREFIX=/usr               \
       -DLLVM_TARGETS_TO_BUILD="host;AMDGPU;BPF" \
       -DLLVM_BINUTILS_INCDIR=/usr/include       \
       -DLLVM_INCLUDE_BENCHMARKS=OFF             \
+      -DCLANG_DEFAULT_PIE_ON_LINUX=ON           \
       -Wno-dev -G Ninja ..                      &amp;&amp;
 ninja</userinput></screen>