to rename svmtrain to libsvmtrain to avoid shaddowing original matlab's svmtrain:
rename svmtrain.c file to libsvmtrain.c
rename libsvmpredict.c file to libsvmpredict.c

in make.m also change libsvmtrain and libsvmpredict in mex file call.

Installing libsvmon my I had some compilation problems.

In matlab:
>> cd(matlabroot)
>> cd bin
>> edit
>> edit
>> edit

replace 10.7 with 10.11 in all of them (macosx10....  link

$ /Applications/ -nodisplay
>> make
// /Applications/ error: unknown type name 'char16_t'
// typedef char16_t CHAR16_T;

To avoid this edit the make file of libsvm and add -Dchar16_t=uint16_t  option to all mex calls. link

Addpath libsvm-3.21/matlab/ before calling

After testing you get (n choose 2)  probbalities or decision values. where if positive it means it belongs to class +1 and if negative it belongs to class -1 in n choose k 2-way classifiers.