texinfo does not compile without libintl.h even though configure checks for it

[Erik A Johnson]

Without libintl.h, tp/Texinfo/XS/parsetexi/api.c does not compile -- even 
though configure tests for libintl.h.  In api.c, is the line

        #include <libintl.h>

actually needed?  (Commenting that line out in texinfo-7.1 allows it to 
compile, complete tests, etc. on macOS Sonoma 14.2.1.)