AC_PROG_CC
AC_PROG_CPP
AC_CHECK_PROGS([YACC], 'bison -y')
-test -z "$YACC" && AC_MSG_WARN([GNU bison not found])
+test -z "$YACC" -a ! -f src/cql.c && AC_MSG_ERROR([GNU Bison not found])
+test -z "$YACC" && AC_MSG_WARN([GNU Bison not found])
AC_CHECK_PROGS([TCLSH], [tclsh tclsh8.5 tclsh8.4 tclsh8.3 tclsh8.2], [tclsh])
AC_PROG_INSTALL
AM_PROG_LIBTOOL
YAZ_DOC
dnl
dnl
-AC_CHECK_HEADERS([dirent.h fnmatch.h wchar.h locale.h langinfo.h pwd.h unistd.h sys/select.h sys/socket.h sys/stat.h sys/time.h sys/times.h sys/types.h sys/un.h sys/wait.h sys/prctl.h netdb.h arpa/inet.h netinet/tcp.h netinet/in_systm.h],[],[],[])
+AC_CHECK_HEADERS([dirent.h fnmatch.h wchar.h locale.h langinfo.h pwd.h unistd.h sys/select.h sys/socket.h sys/stat.h sys/time.h sys/times.h sys/types.h sys/un.h sys/wait.h sys/prctl.h netdb.h arpa/inet.h netinet/tcp.h netinet/in_systm.h execinfo.h],[],[],[])
AC_CHECK_HEADERS([net/if.h netinet/in.h netinet/if_ether.h],[],[],[
#if HAVE_SYS_TYPES_H
#include <sys/types.h>