[PATCH nftables] build: Allow building from tarballs without yacc/lex

[Matt Turner <mattst88@gmail.com>]

The generated files are included in the tarballs already, but
configure.ac was coded to fail if yacc/lex were not found regardless.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 configure.ac | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index a04d94bc..3496e410 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,13 +29,13 @@ AC_PROG_SED
 AM_PROG_LEX
 AC_PROG_YACC
 
-if test -z "$ac_cv_prog_YACC"
+if test -z "$ac_cv_prog_YACC" -a ! -f "${srcdir}/src/parser_bison.c"
 then
         echo "*** Error: No suitable bison/yacc found. ***"
         echo "    Please install the 'bison' package."
         exit 1
 fi
-if test -z "$ac_cv_prog_LEX"
+if test -z "$ac_cv_prog_LEX" -a ! -f "${srcdir}/src/scanner.c"
 then
         echo "*** Error: No suitable flex/lex found. ***"
         echo "    Please install the 'flex' package."
-- 
2.24.1