Global define of MIN

Some OS' provide it automatically, so make sure we define it
conditionally in one place.

src/suricata-common.h

@@ -282,6 +282,10 @@
 #define pcre_free_study pcre_free
 #endif
 
+#ifndef MIN
+#define MIN(x, y) (((x)<(y))?(x):(y))
+#endif
+
 typedef enum PacketProfileDetectId_ {
     PROF_DETECT_MPM,
     PROF_DETECT_MPM_PACKET,         /* PKT MPM */