Add NEWS for 5.2.11 and 5.2.12

NEWS

@@ -826,6 +826,47 @@ XZ Utils Release Notes
       (FreeBSD >= 10).
 
 
+5.2.12 (2023-05-04)
+
+    * Fixed a build system bug that prevented building liblzma as a
+      shared library when configured with --disable-threads. This bug
+      affected releases 5.2.6 to 5.2.11 and 5.4.0 to 5.4.2.
+
+    * Include <intrin.h> for Windows intrinsic functions where they are
+      needed. This fixed a bug that prevented building liblzma using
+      clang-cl on Windows.
+
+    * Minor update to the Croatian translation. The small change
+      applies to a string in both 5.2 and 5.4 branches.
+
+
+5.2.11 (2023-03-18)
+
+    * Removed all possible cases of null pointer + 0. It is undefined
+      behavior in C99 and C17. This was detected by a sanitizer and had
+      not caused any known issues.
+
+    * Build systems:
+
+        - Added a workaround for building with GCC on MicroBlaze Linux.
+          GCC 12 on MicroBlaze doesn't support the __symver__ attribute
+          even though __has_attribute(__symver__) returns true. The
+          build is now done without the extra RHEL/CentOS 7 symbols
+          that were added in XZ Utils 5.2.7. The workaround only
+          applies to the Autotools build (not CMake).
+
+        - CMake: Ensure that the C compiler language is set to C99 or
+          a newer standard.
+
+        - CMake changes from XZ Utils 5.4.1:
+
+            * Added a workaround for a build failure with
+              windres from GNU binutils.
+
+            * Included the Windows resource files in the xz
+              and xzdec build rules.
+
+
 5.2.10 (2022-12-13)
 
     * xz: Don't modify argv[] when parsing the --memlimit* and