Error compiling flex (the lexical analyzer)

I'm trying to install flex (the lexical analyzer, not the Adobe program) on my Windows computer. I have MSYS installed. I untar flex, ./configure it, but when I try to make it, I get th开发者_StackOverflowis error:

In file included from ccl.c:34:
flexdef.h:94:19: error: regex.h: No such file or directory
In file included from ccl.c:34:
flexdef.h:1195: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'regex_linedir'
flexdef.h:1197: error: expected ')' before '*' token
flexdef.h:1198: error: expected ')' before '*' token
flexdef.h:1199: error: expected ')' before '*' token
flexdef.h:1200: error: expected ')' before '*' token
flexdef.h:1201: error: expected ')' before '*' token
flexdef.h:1202: error: expected ')' before '*' token
make[2]: *** [ccl.o] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

Until recently, I've only ever installed things using an .exe, so I'm pretty confused by this. Installing bison and m4 both went smoothly, and I'm wondering why this isn't. Any ideas?

You're missing the regex library, install it and try again.