If you use the command line, C sources must be first by means of qxcc command line tool. This tool just invokes the C compiler installed on your system (in case of Windows - Visual Studio).
Its syntax is as follows:
qxcc [ -32 | -64 ] [ -debug ] [-pic ] [ -c ] [-I<path> ] [-L<path> ] [-lname ] [ -o output_name ] input_files
When you specify a file name and its path, be careful with its case.
UNIX is case-sensitive, so it will treat files which names come in different cases as separate files.
Flag -32 or -64 indicated whether the source is building for 32 or 64 bit system. Flag -o references out_file.obj which is the name of the file which will be the result of the compilation, it may include the path. The input files are the names of the files you want to compile including the path if necessary. The -I flag points at the directory where C headers are located which is typically %LYCIA_DIR\include and where fgifunc.h file should be located. Flag -L<path> points to the directory where libraries are stored and must be followed by the library name.
Here is an example:
qxcc -o "C:\Users\me\workspace\C-lib\output\c2.obj" -I "C:\Program Files\Querix\Lycia/include" "C:\Users\me\workspace\C-lib\source\c2.c"