-AC_DEFUN([AC_PROG_BISON], [AC_CHECK_PROGS(BISON, bison, bison)])
+if test ! -f "$srcdir/formats/ctf/metadata/ctf-parser.h"; then
+ if test x"$YACC" != "xbison -y"; then
+ AC_MSG_ERROR([[bison not found and is required when building from git.
+ Please install bison]])
+ fi
+fi
+
+if test ! -f "$srcdir/formats/ctf/metadata/ctf-lexer.c"; then
+ if test x"$LEX" != "xflex"; then
+ AC_MSG_ERROR([[flex not found and is required when building from git.
+ Please install flex]])
+ fi
+fi
+