[collectd] Collection 4 - Two programs you should check for in configure

[Andreas Maus]

Hi.

While trying to build collection4 I discovered two programs you
should have: flex and yacc (or bison).

The configure script checks for these programs:

checking how to run the C preprocessor... gcc -E
checking for flex... no
checking for lex... no
checking for bison... no
checking for byacc... no
checking for grep that handles long lines and -e... /bin/grep

but it should throw an error if they are not found.

A missing yacc/bison results in:

../ylwrap: line 111: yacc: command not found

With Yacc/Bison and without Flex the error is somehow confusing:

gcc -DHAVE_CONFIG_H -I.  -DPREFIX='"/opt/collection4"' -DCONFIGFILE='"/opt/collection4/etc/collection.conf"'  -Wall -Wextra -g -O2 -c oconfig.c
/bin/sh ../ylwrap scanner.l .c scanner.c -- :
make[2]: *** [scanner.c] Error 1
make[2]: Leaving directory `/home/maus/_/collection4/src'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/home/maus/_/collection4/src'
make: *** [all-recursive] Error 1

To cut a long story short, I think the configure script should exit
with an error if lex/flex and bison/yacc are not found.

So long,

Andreas.