Add a couple comments.

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/env.c b/lib/env.c
index bc23b753..3e05f4e4 100644
--- a/lib/env.c
+++ b/lib/env.c
@@ -36,6 +36,7 @@ void xsetenv(char *name, char *val)
 
   // If we haven't snapshot initial environment state yet, do so now.
   if (!toys.envc) {
+    // envc is size +1 so even if env empty it's nonzero after initialization
     while (environ[toys.envc++]);
     memcpy(new = xmalloc(((toys.envc|0xff)+1)*sizeof(char *)),
       environ, toys.envc*sizeof(char *));
@@ -52,7 +53,7 @@ void xsetenv(char *name, char *val)
     if (val) new = xmprintf("%s=%s", name, val);
   }
 
-  envc = toys.envc-1;
+  envc = toys.envc-1;  // compensate for size +1 above
   for (i = 0; environ[i]; i++) {
     // Drop old entry, freeing as appropriate. Assumes no duplicates.
     if (!memcmp(name, environ[i], len) && environ[i][len]=='=') {