Compile fails with gcc 14.2/clang 18.1

[lrauschning]

Hi all,
had a CI failure caused by a compile error during a pip installation of pypairix (see here).
Tried to compile it manually then and also got compilation errors.
On my linux machine, I get the following error trying to compile with gcc 14.2:

cd src; make; cd ..
make[1]: Entering directory '/home/src/pairix/src'
make[2]: Entering directory '/home/src/pairix/src'
gcc -c -g -w -O2 -fPIC  -D_FILE_OFFSET_BITS=64 -D_USE_KNETFILE -DBGZF_CACHE  index.c -o index.o
index.c: In function ‘ti_querys_2d_general’:
index.c:1219:31: error: initialization of ‘char **’ from incompatible pointer type ‘const char **’ [-Wincompatible-pointer-types]
 1219 |          char **chrpairlist = ti_seqname(t->idx, &n_seqpair_list);
      |                               ^~~~~~~~~~
index.c:1236:59: error: passing argument 2 of ‘ti_querys_2d_multi’ from incompatible pointer type [-Wincompatible-pointer-types]
 1236 |          sequential_iter_t *siter = ti_querys_2d_multi(t, regions, n_sub_list);
      |                                                           ^~~~~~~
      |                                                           |
      |                                                           char **
In file included from index.c:11:
pairix.h:131:73: note: expected ‘const char **’ but argument is of type ‘char **’
  131 |         sequential_iter_t *ti_querys_2d_multi(pairix_t *t, const char **regs, int nRegs);
      |                                                            ~~~~~~~~~~~~~^~~~
index.c:1246:31: error: initialization of ‘char **’ from incompatible pointer type ‘const char **’ [-Wincompatible-pointer-types]
 1246 |          char **chrpairlist = ti_seqname(t->idx, &n_seqpair_list);
      |                               ^~~~~~~~~~
index.c:1263:59: error: passing argument 2 of ‘ti_querys_2d_multi’ from incompatible pointer type [-Wincompatible-pointer-types]
 1263 |          sequential_iter_t *siter = ti_querys_2d_multi(t, regions, n_sub_list);
      |                                                           ^~~~~~~
      |                                                           |
      |                                                           char **
pairix.h:131:73: note: expected ‘const char **’ but argument is of type ‘char **’
  131 |         sequential_iter_t *ti_querys_2d_multi(pairix_t *t, const char **regs, int nRegs);
      |                                                            ~~~~~~~~~~~~~^~~~
index.c: In function ‘ti_query_2d_tid’:
index.c:1417:31: error: returning ‘ti_iter_t’ {aka ‘struct __ti_iter_t *’} from a function with return type ‘int’ makes integer from pointer without a cast [-Wint-conversion]
 1417 |         if (name == 0) return ti_iter_first();
      |                               ^~~~~~~~~~~~~~~
index.c: In function ‘get_unique_merged_seqname’:
index.c:1643:22: error: assignment to ‘char **’ from incompatible pointer type ‘const char **’ [-Wincompatible-pointer-types]
 1643 |             seqnames = ti_seqname(tbs[i]->idx,&len);
      |                      ^
index.c: In function ‘check_triangle’:
index.c:1971:23: error: initialization of ‘char **’ from incompatible pointer type ‘const char **’ [-Wincompatible-pointer-types]
 1971 |     char **seqnames = ti_seqname(idx,&len);
      |                       ^~~~~~~~~~
make[2]: *** [Makefile:15: index.o] Error 1
make[2]: Leaving directory '/home/src/pairix/src'
make[1]: *** [Makefile:18: all-recur] Error 1
make[1]: Leaving directory '/home/src/pairix/src'

And a similar error running the compile with clang 18.1:

cd src; make; cd ..
make[1]: Entering directory '/home/src/pairix/src'
make[2]: Entering directory '/home/src/pairix/src'
clang -c -g -w -O2 -fPIC  -D_FILE_OFFSET_BITS=64 -D_USE_KNETFILE -DBGZF_CACHE  index.c -o index.o
index.c:1417:24: error: incompatible pointer to integer conversion returning 'ti_iter_t' (aka 'struct __ti_iter_t *') from a function with result type 'int' [-Wint-conversion]
 1417 |         if (name == 0) return ti_iter_first();
      |                               ^~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [Makefile:15: index.o] Error 1
make[2]: Leaving directory '/home/src/pairix/src'
make[1]: *** [Makefile:18: all-recur] Error 1
make[1]: Leaving directory '/home/src/pairix/src'

Also, pypi still seems to be on version 0.3.7.
Happy to contribute to fix this, but would appreciate some pointers – I'm a bit wary of messing with types in a large C codebase.

Cheers and happy winter holidays,
Leon