topo/treematch: squash some compiler warnings

Only define MIN/MAX if they are not already defined.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>

ompi/mca/topo/treematch/treematch/tm_kpartitioning.c

@@ -15,8 +15,9 @@ static int verbose_level = ERROR;
 #define MAX_TRIALS 10
 #define USE_KL_STRATEGY 1
 
-
+#if !defined(MIN)
 #define MIN(a,b) ((a)<(b)?(a):(b))
+#endif
 
 
 int  fill_tab(int **,int *,int,int,int,int);

ompi/mca/topo/treematch/treematch/tm_tree.c

@@ -12,8 +12,12 @@
 #include "tm_thread_pool.h"
 
 
+#if !defined(MIN)
 #define MIN(a,b) ((a)<(b)?(a):(b))
+#endif
+#if !defined(MAX)
 #define MAX(a,b) ((a)>(b)?(a):(b))
+#endif
 
 #ifndef __CHARMC__
 #define __CHARMC__ 0