diff --git a/source/compiler/sc2.c b/source/compiler/sc2.c
index 399b618..a7a5ca5 100644
--- a/source/compiler/sc2.c
+++ b/source/compiler/sc2.c
@@ -1832,21 +1832,22 @@ static void substallpatterns(unsigned char *line,int buffersize)
 }
 #endif
 
-static void doconcat(const char *line)
+static void ppconcat(const char *line)
 {
-  register int i;
-  const char *p, *b;
-  for (i=0; *(line+i)!='\0'; ++i) {
-    if (*(line+i)=='#' && *(line+i+1)=='#') {
-      p=line+i-1;
-      b=line+i+2;
+  register const char *c, *p, *b;
+  for (c=line; *c!='\0'; ++c) {
+    if (is_startstring(c))
+      c=skipstring(c);
+    if(*c=='#' && *(c+1)=='#') {
+      p=c-1;
+      b=c+2;
       while (*p==' ')
         p--;
       while (*b==' ')
         b++;
-      strcpy((char*)p+1, b);
+      strcpy((char*)p+1,b);
     } /* if */
-  } /* for */
+  } /* switch */
 }
 
 /*  preprocess
@@ -1872,14 +1873,14 @@ SC_FUNC void preprocess(void)
     stripcom(pline);    /* ??? no need for this when reading back from list file (in the second pass) */
     lptr=pline;         /* set "line pointer" to start of the parsing buffer */
     iscommand=command();
-    doconcat(lptr);
+    ppconcat((char*)lptr);
     if (iscommand!=CMD_NONE)
       errorset(sRESET,0); /* reset error flag ("panic mode") on empty line or directive */
     #if !defined NO_DEFINE
       if (iscommand==CMD_NONE) {
         assert(lptr!=term_expr);
         substallpatterns(pline,sLINEMAX);
-        doconcat(pline);
+        ppconcat((char*)pline);
         lptr=pline;       /* reset "line pointer" to start of the parsing buffer */
       } /* if */
     #endif