Extract Text from Rich Text Format (RTF) Documents
Wraps the 'unrtf' utility to extract text from RTF files. Supports
document conversion to HTML, LaTeX or plain text. Output in HTML is recommended
because 'unrtf' has limited support for converting between character encodings.
Fix for sys 2.0 (do not quote arg on Windows)
Link unrtf executable with $(LIBS) hopefully fixes Solaris
Fix format-truncation warning in GCC-7
Replace sprintf() by snprintf() to fix a new warning in gcc-7