The declaration of the two-dimensional arrays hori and vert prevents compilation of test-vector.c with GCC 14 because of a conflicting declaration of function giza_vector_float using the argument type (const float *) for those variables. Compilation succeeds after modifying the function call

giza_vector_float (n, m, hori, vert, 0, 1, 0, 1, scale, 0, affine, 1000.);

by casting the types of arguments hor and vert according to the declaration of giza_vector_float, thus

giza_vector_float (n, m, (float *) &hori, (float *) &vert, 0, 1, 0, 1, scale, 0, affine, 1000.); .

It might be preferable though to adjust the declaration of giza_vector_float etc. in giza.h using variable length arrays instead.