I get:

2>backend/gsl/parser.y(53): warning C4820: 'param': '4' bytes padding added after data member 'pos'
2>D:/LabPlot/src/gsl_parser.c(1086): warning C4242: '=': conversion from 'int' to 'yytype_int16', possible loss of data
2>backend/gsl/parser.y(114): warning C4255: 'parse_errors': no function prototype given: converting '()' to '(void)'
2>backend/gsl/parser.y(305): warning C4267: '+=': conversion from 'size_t' to 'unsigned int', possible loss of data
2>backend/gsl/parser.y(327): warning C4242: '=': conversion from 'int' to 'char', possible loss of data