fix some typos in comments I found while reading Nbase's code

nbase/nbase_misc.c

@@ -740,7 +740,7 @@ char *format_bytecount(unsigned long long bytes, char *buf, size_t buflen) {
 
 /* Compare a canonical option name (e.g. "max-scan-delay") with a
    user-generated option such as "max_scan_delay" and returns 0 if the
-   two values are considered equivalant (for example, - and _ are
+   two values are considered equivalent (for example, - and _ are
    considered to be the same), nonzero otherwise. */
 int optcmp(const char *a, const char *b) {
   while(*a && *b) {

nbase/nbase_winconfig.h

@@ -97,7 +97,7 @@
 #define NBASE_WINCONFIG_H
 //This disables the warning 4800 http://msdn.microsoft.com/en-us/library/b6801kcy(v=vs.71).aspx
 #pragma warning(disable : 4800)
-/* It doesn't really have strucct IP, but we use a different one instead
+/* It doesn't really have struct IP, but we use a different one instead
 	of the one that comes with Nmap */
 #define HAVE_STRUCT_IP 1
 /* #define HAVE_STRUCT_ICMP 1 */

nbase/snprintf.c

@@ -1,6 +1,6 @@
 /* Note -- this file was obtained from tcpdump-2000-9-17 CVS snapshot *
  * ( www.tcpdump.org).  It has been modified slightly for             *
- * compatability with libnbase.  Modification etails may be in the    *
+ * compatability with libnbase.  Modification details may be in the    *
  * nbase CHANGELOG - fyodor@nmap.org                              */