Error building flex

[testhound]

After following the instructions for configuring to build flex I receive the following errors:

gcc -DHAVE_CONFIG_H -I. -DLOCALEDIR="/usr/local/share/locale" -g -O2 -MT flex-yylex.o -MD -MP -MF .deps/flex-yylex.Tpo -c -o flex-yylex.o test -f 'yylex.c' || echo './'yylex.c mv -f .deps/flex-yylex.Tpo .deps/flex-yylex.Po /bin/bash ../build-aux/ylwrap scan.l lex.yy.c scan.c -- flex
"/home/collison/OpenSource/flex/src/scan.l", line 3: unrecognized '%' directive "/home/collison/OpenSource/flex/src/scan.l", line 6: bad character: # "/home/collison/OpenSource/flex/src/scan.l", line 6: unknown error processing section 1 "/home/collison/OpenSource/flex/src/scan.l", line 6: unknown error processing section 1 "/home/collison/OpenSource/flex/src/scan.l", line 6: bad character: " "/home/collison/OpenSource/flex/src/scan.l", line 6: unknown error processing section 1 "/home/collison/OpenSource/flex/src/scan.l", line 6: bad character: . "/home/collison/OpenSource/flex/src/scan.l", line 6: unknown error processing section 1 "/home/collison/OpenSource/flex/src/scan.l", line 6: bad character: " "/home/collison/OpenSource/flex/src/scan.l", line 7: bad character: }

Any help would be appreciated.

[Mightyjo]

Sorry it's taken so long to get you an answer on this. It looks like this bug was fixed in version 2.6.4 by 7f263e3. A note in the ChangeLog mentions it:

2017-01-09  luistung <[email protected]>

	* src/scan.l: scanner: join symbol list.  Removed a newline that caused a problem building the scanner in some
	circumstances. Specifically: 'bad character' error  when executing /bin/sh ../build-aux/ylwrap scan.l lex.yy.c scan.c -- flex

If you can't upgrade but you can rebuild flex, the fix is pretty simple. Just join the two red lines in the diff at the commit link.

[alpengjs]

Encountered the same problem. It is due to my flex is too old :

# /router/bin/flex --version /router/bin/flex version 2.5.4

Using a newer version of flex v2.6.1 is able to compile v2.6.4

[vkottler]

Using a newer version of flex v2.6.1 is able to compile v2.6.4

What's actually causing this though? Why is some random system-installed flex relevant to the compilation of this project?