Fix pvode warnings

[dschwoerer]

Resolves: #2654

[ZedThree]

This is almost certainly fine, though I worry the format string change will just give a warning in a different place. Do we still test with clang any more?

[dschwoerer]

The string is only used once - so it would only trigger if the int type is changed

[dschwoerer]

And g++ also warns about this:

/builddir/build/BUILD/BOUT-dev-5.0.0/externalpackages/PVODE/source/cvode.cpp: In function 'void* pvode::CVodeMalloc(integer, RhsFn, real, N_Vector, int, int, int, real*, void*, void*, FILE*, int, long int*, real*, void*)':
/builddir/build/BUILD/BOUT-dev-5.0.0/externalpackages/PVODE/source/cvode.cpp:178:25: warning: format '%ld' expects argument of type 'long int', but argument 3 has type 'pvode::integer' {aka 'int'} [-Wformat=]
  178 | #define CVM             "CVodeMalloc-- "
      |                         ^
/builddir/build/BUILD/BOUT-dev-5.0.0/externalpackages/PVODE/source/cvode.cpp:182:25: note: in expansion of macro 'CVM'
  182 | #define MSG_BAD_N       CVM "N=%ld < 1 illegal.\n\n"
      |                         ^~~
/builddir/build/BUILD/BOUT-dev-5.0.0/externalpackages/PVODE/source/cvode.cpp:496:17: note: in expansion of macro 'MSG_BAD_N'
  496 |     fprintf(fp, MSG_BAD_N, N);
      |                 ^~~~~~~~~
/builddir/build/BUILD/BOUT-dev-5.0.0/externalpackages/PVODE/source/cvode.cpp:182:34: note: format string is defined here
  182 | #define MSG_BAD_N       CVM "N=%ld < 1 illegal.\n\n"
      |                                ~~^
      |                                  |
      |                                  long int
      |                                %d

[ZedThree]

Ah, just looked myself too, only used in a single place with an int so %d is always correct, ok happy to merge now.