:loop
/\\$/N
/\\$/b loop
s!@INCDIR@!$(INCDIR)!g
s!@BFDDIR@!$(BFDDIR)!g
s!@SRCDIR@/!!g
s/\\\n */ /g
s/ *$//
s/ */ /g
/:$/d
s/\(.\{50\}[^ ]*\) /\1 \\\
/g