FESTVOX Installation issue

[shrishtis7]

Hi everyone, I am trying to install festvox2.8 and getting the following error:

making in . ...
making in src ...
making in src/general ...
making in src/diphones ...
making in src/eval ...
making in src/promptselect ...
making in src/vc ...
making in src/vc/src ...
making in src/vc/src/sp ...
making in src/vc/src/sub ...
g++ -g -O2 -Wall -c gmm_sub.cc -o gmm_sub.o
gmm_sub.cc: In function ‘double get_gauss_jde_dia(long int, DVECTOR, DVECTOR, DMATRIX, DMATRIX, DMATRIX)’:
gmm_sub.cc:763:16: warning: variable ‘clsnum’ set but not used [-Wunused-but-set-variable]
763 | long k, b, clsnum, dim, dim2;
| ^~~~
gmm_sub.cc: In function ‘DVECTOR_STRUCT* xget_sumgvec_gammamat_file(char*, long int, long int, char*)’:
gmm_sub.cc:1028:43: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
1028 | if ((ifp = fopen(gaussmatfile, "rb")) == NUL) {
gmm_sub.cc:1032:43: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
1032 | if ((ofp = fopen(gammamatfile, "wb")) == NUL) {
make[4]: * [Makefile:60: gmm_sub.o] Error 1
making in src/vc/src/analysis ...
g++ -o analysis main.o analysis_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: analysis] Error 1
making in src/vc/src/extdim ...
g++ -o extdim main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: extdim] Error 1
making in src/vc/src/f0stats ...
g++ -o f0stats main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: f0stats] Error 1
making in src/vc/src/gmmpara ...
g++ -o gmm_para main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:64: gmm_para] Error 1
making in src/vc/src/vqlbl ...
g++ -o vqlbl main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:66: vqlbl] Error 1
making in src/vc/src/cov2dia ...
g++ -o cov2dia main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:66: cov2dia] Error 1
making in src/vc/src/extfrm ...
g++ -o extfrm main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: extfrm] Error 1
making in src/vc/src/gmm ...
g++ -o gmm_jde main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: gmm_jde] Error 1
making in src/vc/src/utt2f0 ...
g++ -o utt2f0 main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: utt2f0] Error 1
making in src/vc/src/dtw ...
g++ -o dtw main.o dtw_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:66: dtw] Error 1
making in src/vc/src/f0map ...
g++ -o f0map main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:65: f0map] Error 1
making in src/vc/src/gmmmap ...
g++ -o gmmmap main.o gmmmap_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:66: gmmmap] Error 1
making in src/vc/src/jdmat ...
g++ -o jdmat main.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:64: jdmat] Error 1
making in src/vc/src/mlpg ...
g++ -o mlpg main.o mlpg_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:67: mlpg] Error 1
making in src/vc/src/synthesis ...
g++ -o synthesis main.o synthesis_sub.o vocoder_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:67: synthesis] Error 1
making in src/vc/src/vq ...
g++ -o lbg main.o vq_sub.o -L../lib -lsub -lsp
/usr/bin/ld: cannot find -lsub: No such file or directory
collect2: error: ld returned 1 exit status
make[4]: * [Makefile:66: lbg] Error 1
make[3]: * [../../../config/common_make_rules:65: .make_build_dirs] Error 2
make[2]: * [../..//config/common_make_rules:65: .make_build_dirs] Error 2
making in src/ehmm ...
making in src/ehmm/src ...
making in src/ehmm/scripts ...
install -p comp_dcep.pl phfromutt.pl scale_feat.pl sym2nm.pl seqproc.pl do_ehmm check_lab.pl sl2nm.pl rem_ssil.pl rm_nan_utts ../bin
cp -p phseq.scm ../bin
making in src/interslice ...
making in src/interslice/src ...
making in src/interslice/scripts ...
making in src/mllr ...
making in src/spamf0 ...
making in src/phrasyn ...
making in src/grapheme ...
making in src/lts ...

I have already installed speech tools2.5 and festival2.5 successfully. I am not able to get past this error. I have tried installing libsub using "sudo apt-get install libsub-dev" but I am getting this message - "E: Unable to locate package libsub-dev
".
Could someone please help me with resolving this error?