in config.c, isolateValue there is code which appears to be trying to handle trimming off trailing spaces/tabs (checked via glibc's isblank 
function).  Basically before the trailing space check chptr gets left point to the '\n' so trailing spaces never get clipped.

which since chptr is now always left of the '\n', the final if is no longer needed as well.

found when I accidently left a trailing space in an olddir directive ' olddir /var/log/archive '

Here is a patch:
--- orig.config.c       Sat Sep  2 16:46:02 2000
+++ config.c    Sat Sep  2 16:45:51 2000
@@ -53,12 +53,11 @@
 
     while (*chptr != '\n') chptr++;
 
+    chptr--; /* move to the left of the '\n' */
+
     while (isblank(*chptr)) chptr--;
 
-    if (*chptr == '\n')
-       *endPtr = chptr;
-    else
-       *endPtr = chptr + 1;
+    *endPtr = chptr + 1;
 
     return 0;
 }