[amiwm] Do another pass to clean up build warnings

This is mostly a "dangling if" cleanup, but I did add some other
comments here and there!

libami/Makefile.in

@@ -8,7 +8,7 @@ RANLIB = @RANLIB@
 CFLAGS = @CFLAGS@
 YFLAGS = -d
 DEFS = @DEFS@
-ALL_CFLAGS = -I@srcdir@ -I@top_srcdir@ $(DEFS) $(CFLAGS) @X_CFLAGS@
+ALL_CFLAGS = -Wall -I@srcdir@ -I@top_srcdir@ $(DEFS) $(CFLAGS) @X_CFLAGS@
 LIBS = @X_LIBS@ @X_PRE_LIBS@ -lXext -lXmu -lX11 @X_EXTRA_LIBS@ @LIBS@
 prefix = @prefix@
 exec_prefix = @exec_prefix@

libami/error.c

@@ -40,7 +40,7 @@ BOOL Fault(LONG code, UBYTE *header, UBYTE *buffer, LONG len)
     strcpy((char *)buffer, syserrmsg[code-MIN_ERRNO]);
   } else {
     char number[6+4*sizeof(LONG)];
-    sprintf(number, "Error %ld", code);
+    sprintf(number, "Error %ld", (long int) code);
     if(len<strlen(number)+1)
       return FALSE;
     strcpy((char *)buffer, number);

libami/iconlib.c

@@ -505,12 +505,13 @@ struct DiskObject *GetDefDiskObject(LONG def_type)
 
   if(def_type<WBDISK || def_type>WBAPPICON)
     return NULL;
-  if(!icondir)
-    if(!(icondir = get_current_icondir()))
+  if(!icondir) {
+    if(!(icondir = get_current_icondir())) {
       return NULL;
-    else
+    } else {
       l = strlen(icondir);
-
+    }
+  }
 #ifdef HAVE_ALLOCA
   buf = alloca(l+18);
 #else

libami/lists.c

@@ -2,6 +2,8 @@
 
 #ifndef AMIGAOS
 
+#include <string.h>
+
 void NewList(struct List *list)
 {
   list->lh_TailPred = (struct Node *)&list->lh_Head;