Patch for fixing parallel make issue, bug #486434

Related links:

https://github.com/brianb/mdbtools/issues/33
https://github.com/brianb/mdbtools/issues/35

diff --git a/src/sql/Makefile.am b/src/sql/Makefile.am
index 633f0c3..94b0838 100644
--- a/src/sql/Makefile.am
+++ b/src/sql/Makefile.am
@@ -1,3 +1,5 @@
+BUILT_SOURCES = parser.h
+AM_YFLAGS = -d
 lib_LTLIBRARIES	=	libmdbsql.la
 libmdbsql_la_SOURCES=	mdbsql.c parser.y lexer.l 
 libmdbsql_la_LDFLAGS = -version-info 2:0:0 -export-symbols-regex '^mdb_sql_'