Fixed off-by-one error in findBinaryInPath() (thanks, Dmitry!).

This bug is new to the development branch, and doesn't exist in either the
 stable-1.0 or stable-2.0 branches.

docs/CREDITS.txt

@@ -133,6 +133,9 @@ Haiku fixes:
 SLB archiver:
     Aleksi Nurmi
 
+Bug fixes:
+    Dmitry Marakasov
+
 Other stuff:
     Your name here! Patches go to icculus@icculus.org ...
 

src/platform_unix.c

@@ -193,7 +193,7 @@ static char *findBinaryInPath(const char *bin, char *envr)
 
         if (access(exe, X_OK) == 0)  /* Exists as executable? We're done. */
         {
-            exe[size - binlen] = '\0'; /* chop off filename, leave '/' */
+            exe[(size - binlen) - 1] = '\0'; /* chop off filename, leave '/' */
             return exe;
         } /* if */