Fix compiler errors on FreeBSD.

Fixes #93.

src/uv-freebsd.c

@@ -20,25 +20,29 @@
 
 #include "uv.h"
 
+#include <string.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
 
 int uv_exepath(char* buffer, size_t* size) {
   uint32_t usize;
   int result;
   char* path;
   char* fullpath;
+  int mib[4];
+  size_t cb;
 
   if (!buffer || !size) {
     return -1;
   }
 
-  int mib[4];
 
   mib[0] = CTL_KERN;
   mib[1] = KERN_PROC;
   mib[2] = KERN_PROC_PATHNAME;
   mib[3] = -1;
 
-  size_t cb = *size;
+  cb = *size;
   if (sysctl(mib, 4, buffer, &cb, NULL, 0) < 0) {
 	  *size = 0;
 	  return -1;