Hi. In RHEL 6.6 and later they moved libfl.a into the separate package "flex-devel", available only to subscribers. "flex" package is still on RHEL DVD and part of 'Development Tools' group.
See https://rhn.redhat.com/errata/RHBA-2014-1402.html When configure run on systems without flex-devel, but with 'Development Tools' installed, the result is: checking for flex... flex checking lex output file root... lex.yy checking lex library... none needed checking whether yytext is a pointer... no After installing flex-devel it's: checking for flex... flex checking lex output file root... lex.yy checking lex library... -lfl checking whether yytext is a pointer... yes I created the configure script with fairly recent autoconf 2.69 from ArchLinux. I think the check should not be successful unless it finds a way to compile a test program with CC (currently _all_ compilations fail with either "cannot find -lfl" or "undefined reference to `yywrap'") Maybe it could try whether flex supports "--noyywrap".
