lex: %option not supported by solaris lex

it turns out that we don't need to tell lex we don't plan to use unput;
we can just.... not use unput. however, if we're flex, use the command
line option if it's available, to avoid warnings

configure.ac

@@ -59,6 +59,9 @@ fi
 dnl AC_KRB_PROG_YACC
 AC_PROG_YACC
 AM_PROG_LEX
+AS_IF([$LEX --nounput -V > /dev/null 2>&1 && test $? -eq 0],
+      [AC_SUBST([FLEXNOUNPUTARGS], ["--nounput"])],
+      [AC_SUBST([FLEXNOUNPUTARGS], [""])])
 dnl AC_PROG_RANLIB
 AC_PROG_AWK
 AC_KRB_PROG_LN_S

lib/com_err/Makefile.am

@@ -3,6 +3,7 @@
 include $(top_srcdir)/Makefile.am.common
 
 YFLAGS = -d
+LFLAGS = @FLEXNOUNPUTARGS@
 
 lib_LTLIBRARIES = libcom_err.la
 libcom_err_la_LDFLAGS = -version-info 2:3:1

lib/com_err/lex.l

@@ -53,8 +53,6 @@ static int getstring(void);
 
 %}
 
-%option nounput
-
 %%
 et			{ return ET; }
 error_table		{ return ET; }

lib/sl/Makefile.am

@@ -9,6 +9,7 @@ endif
 AM_CPPFLAGS += $(ROKEN_RENAME)
 
 YFLAGS = -d
+LFLAGS = @FLEXNOUNPUTARGS@
 
 include_HEADERS = sl.h
 

lib/sl/slc-lex.l

@@ -53,8 +53,6 @@ static char * handle_string(void);
 
 %}
 
-%option nounput
-
 %%
 [A-Za-z][-A-Za-z0-9_]*	{
 			  yylval.string = strdup ((const char *)yytext);