macro and @iftex fix
Fix upstream build structure for Debian

gccintro.texi
No  blank page insertion for the PDF-reader and single sided printer
No  @ifinfo since we need top page for HTML
Add GFDL for HTML
Add Index for HTML

fdl.texi
No  smallerfonts for HTML/info
chg @unnumberedsubsec -> @headinng
fix typo in README command line