Let us try this again, leave the never-interactive option for the lexers.

Set never-interactive option in lexers so that Flex doesn't use isatty() function from unistd.
Define YY_NO_UNISTD_H when no unistd.h is detected.
Remove attempt to fix isatty error on Windows introduced in  2f780609.
cherry picked from commit c046bb88e5

lib/framework/frame.h

@@ -123,10 +123,7 @@ extern UDWORD HashStringIgnoreCase( const char *String );
 
 struct timezone;
 extern int gettimeofday(struct timeval* tv, struct timezone* tz);
-
-extern "C" int isatty(int);  // Apparently flex declares isatty with C++ linkage on Windows. Don't ask why. Declaring here instead.
 #endif
-extern "C" int isatty(int);  // Apparently flex declares isatty with C++ linkage on Windows. Don't ask why. Declaring here instead.
 
 static inline WZ_DECL_CONST const char * bool2string(bool var)
 {

lib/framework/resource_lexer.l

@@ -80,7 +80,7 @@ extern void res_set_debug(int bdebug);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option prefix="res_"
 
 %x COMMENT

lib/framework/strres_lexer.l

@@ -84,7 +84,7 @@ extern void strres_set_debug(int bdebug);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option prefix="strres_"
 
 %x COMMENT

lib/gamelib/audp_lexer.l

@@ -84,7 +84,7 @@ extern void audp_set_extra(YY_EXTRA_TYPE user_defined);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option prefix="audp_"
 
 %x COMMENT

lib/script/chat_lexer.l

@@ -80,6 +80,7 @@ static SDWORD playerIndex;
 %option prefix="chat_"
 %option nounput
 %option case-insensitive
+%option never-interactive
 
 %%
 

lib/script/script_lexer.l

@@ -458,6 +458,7 @@ static void pushInclude(const char *pIncludePath)
 %option prefix="scr_"
 %option nounput
 %option yylineno
+%option never-interactive
 
 %x COMMENT
 %x SLCOMMENT

src/level_lexer.l

@@ -87,7 +87,7 @@ extern void lev_set_extra(YY_EXTRA_TYPE user_defined);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option prefix="lev_"
 
 %x COMMENT

src/message_lexer.l

@@ -79,7 +79,7 @@ extern void message_set_debug(int bdebug);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option prefix="message_"
 
 %x COMMENT

src/scriptvals_lexer.l

@@ -92,7 +92,7 @@ extern void scrv_set_extra(YY_EXTRA_TYPE user_defined);
 
 %}
 
-%option yylineno noyywrap nounput
+%option yylineno noyywrap nounput never-interactive
 %option warn nodefault
 %option prefix="scrv_"