Re: [PATCH] Fix LEXLIB and YYTEXT_POINTER on non-ANSI systems.

[Paul Eggert]

On 01/04/12 01:06, Peter Rosin wrote:
> Or did you mean that configure should only #define YY_NO_UNISTD_H
> when there is no unistd.h (ac_cv_header_unistd_h=no)?

Yes, that's the idea, it should define YY_NO_UNISTD_H as
needed.  Something like the following.  Does this work for you?

autoconf: don't assume unistd.h when checking lex
* lib/autoconf/programs.m4 (_AC_PROG_LEX_YYTEXT_DECL):
Define YY_NO_UNISTD_H if there's no unistd.h; this
works around a flex bug.  Problem reported by Peter Rosin in:
http://lists.gnu.org/archive/html/autoconf-patches/2011-12/msg00011.html
diff --git a/lib/autoconf/programs.m4 b/lib/autoconf/programs.m4
index 2013a7a..24ccc19 100644
--- a/lib/autoconf/programs.m4
+++ b/lib/autoconf/programs.m4
@@ -718,7 +718,13 @@ fi])
 # Check for the Lex output root, the Lex library, and whether Lex
 # declares yytext as a char * by default.
 m4_define([_AC_PROG_LEX_YYTEXT_DECL],
-[cat >conftest.l <<_ACEOF[
+[AC_CHECK_HEADERS_ONCE([unistd.h])
+cat >conftest.l <<_ACEOF[
+%{
+#ifndef HAVE_UNISTD_H
+# define YY_NO_UNISTD_H 1
+#endif
+%}
 %%
 a { ECHO; }
 b { REJECT; }