diff --git a/acconfig.h b/acconfig.h
index 4e22afc2..b8fd2efe 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -181,6 +181,9 @@
 /* Define if you have the wait3 system call.  */
 #undef HAVE_WAIT3
 
+/* Define if you have the wait3 system call.  */
+#undef HAVE_ZLIB
+
 /* Define as __inline if that's what the C compiler calls it.  */
 #undef inline
 
diff --git a/configure.in b/configure.in
index b475cc16..d0f2a71f 100644
--- a/configure.in
+++ b/configure.in
@@ -211,6 +211,14 @@ AC_CHECK_HEADERS( \
 	fcntl.h getopt.h malloc.h memory.h stdlib.h sys/param.h sys/stat.h \
         sys/time.h sys/timeb.h unistd.h windows.h winbase.h values.h )
 
+# Check for system installed zlib
+AC_CHECK_HEADER(zlib.h)
+if test "x$ac_cv_header_zlib_h" = "xyes"; then
+    AC_DEFINE( HAVE_ZLIB )
+else
+    echo "no zlib found, using version provided by SimGear."
+fi
+
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
 AC_TYPE_SIZE_T
diff --git a/src/BuildTiles/Main/Makefile.am b/src/BuildTiles/Main/Makefile.am
index 8f78f563..9bbbbe97 100644
--- a/src/BuildTiles/Main/Makefile.am
+++ b/src/BuildTiles/Main/Makefile.am
@@ -15,7 +15,7 @@ fgfs_construct_LDADD = \
 	$(top_builddir)/src/Lib/Polygon/libPolygon.a \
 	$(top_builddir)/src/Lib/poly2tri/libpoly2tri.a \
 	$(top_builddir)/src/Lib/Triangle/libTriangle.a \
-	-lsgbucket -lsgmath -lsgmisc -lsgdebug -lz -lgpc
+	-lsgbucket -lsgmath -lsgmisc -lsgdebug -lplibsg -lz -lgpc
 
 fgfs_master_SOURCES = master.cxx
 
diff --git a/src/BuildTiles/Main/main.cxx b/src/BuildTiles/Main/main.cxx
index e700736e..183b602d 100644
--- a/src/BuildTiles/Main/main.cxx
+++ b/src/BuildTiles/Main/main.cxx
@@ -397,7 +397,7 @@ static Point3D calc_normal( FGConstruct& c, int i ) {
     v1[0] = p2.x() - p1.x(); v1[1] = p2.y() - p1.y(); v1[2] = p2.z() - p1.z();
     v2[0] = p3.x() - p1.x(); v2[1] = p3.y() - p1.y(); v2[2] = p3.z() - p1.z();
 
-    sgVectorProduct( normal, v1, v2 );
+    sgVectorProductVec3( normal, v1, v2 );
     sgNormalizeVec3( normal );
 
     return Point3D( normal[0], normal[1], normal[2] );
@@ -665,7 +665,7 @@ void usage( const string name ) {
 }
 
 
-main(int argc, char **argv) {
+int main(int argc, char **argv) {
     double lon, lat;
 
     fglog().setLogLevels( FG_ALL, FG_DEBUG );
@@ -791,4 +791,5 @@ main(int argc, char **argv) {
     }
 
     cout << "[Finished successfully]" << endl;
+    return 0;
 }
diff --git a/src/BuildTiles/Main/master.cxx b/src/BuildTiles/Main/master.cxx
index 69841421..135bd024 100644
--- a/src/BuildTiles/Main/master.cxx
+++ b/src/BuildTiles/Main/master.cxx
@@ -103,7 +103,7 @@ void usage( const string name ) {
 }
 
 
-main(int argc, char **argv) {
+int main(int argc, char **argv) {
     double lon, lat;
 
     if ( argc < 3 ) {
@@ -147,6 +147,8 @@ main(int argc, char **argv) {
 
 	lat += dy;
     }
+
+    return 0;
 }
 
 
diff --git a/src/Include/config.h.in b/src/Include/config.h.in
index b8b419d0..96fdb02a 100644
--- a/src/Include/config.h.in
+++ b/src/Include/config.h.in
@@ -47,6 +47,9 @@
 /* Define if you have the vprintf function.  */
 #undef HAVE_VPRINTF
 
+/* Define if you have the wait3 system call.  */
+#undef HAVE_ZLIB
+
 /* Define as the return type of signal handlers (int or void).  */
 #undef RETSIGTYPE