$sudo apt-get install flex bison
Then change line 54 in ./src-common/yglue.h
size_t yyget_leng (void);
int yyget_leng (void);
This is because one thing is expecting one data type and its like nah its something else, thanks to this post I was able to find the fix.
Then go along as usual...
Missing input file
cfdg - 2.2.1(v11)
cfdg [options] input.cfdg [output.png/svg]
or to pipe a cfdg file on standard input:
cfdg [options] - [output.png/svg]
The output file name is omitted if the -o option is used
Options: ... etc
HOORAY! I'm thinking of adding some group tag support based on rule names from CFDG grammar to the output SVG files. I don't know C++, but I got a C- in the college class for it.