This patch updates the integer types used in two of the dolfin header files.
The changes enable building with gcc-13 and above.

See <https://gcc.gnu.org/gcc-13/porting_to.html> for the porting notes.

See <https://bitbucket.org/fenics-project/dolfin/commits/d56b1b082c50d846fb5bbe4971799ab9ecb21a24> for the upstream fix.

--- a/dolfin/common/timing.h
+++ b/dolfin/common/timing.h
@@ -39,7 +39,7 @@
   ///
   /// Precision of wall is around 1 microsecond, user and system are around
   /// 10 millisecond (on Linux).
-  enum class TimingType : int32_t { wall = 0, user = 1, system = 2 };
+  enum class TimingType : int { wall = 0, user = 1, system = 2 };
 
   /// Start timing (should not be used internally in DOLFIN!)
   void tic();

--- a/dolfin/mesh/MeshConnectivity.h
+++ b/dolfin/mesh/MeshConnectivity.h
@@ -24,5 +24,7 @@
 #include <vector>
 #include <dolfin/log/log.h>
 
+#include <cstdint>
+
 namespace dolfin
 {