Fixed off-by-one error in string allocation.

diff --git a/misc/options.c b/misc/options.c
index aac9e21..ea5729a 100644
--- a/misc/options.c
+++ b/misc/options.c
@@ -156,7 +156,7 @@
         for (i = 0; i < count; i++) len += strlen(argv[pos+i]) + 1;
         if (inherit_str)
         {
-            if (!(inherit_str = realloc( inherit_str, strlen(inherit_str) + len )))
+            if (!(inherit_str = realloc( inherit_str, strlen(inherit_str) + 1 + len )))
                 out_of_memory();
             strcat( inherit_str, " " );
         }