Index: qemu/qemu-doc.texi
===================================================================
--- qemu.orig/qemu-doc.texi	2007-12-11 19:00:53.000000000 -0700
+++ qemu/qemu-doc.texi	2007-12-11 19:16:28.000000000 -0700
@@ -2437,6 +2437,17 @@
 Act as if the host page size was 'pagesize' bytes
 @end table
 
+Environment variables:
+
address@hidden @env
address@hidden QEMU_STRACE
+Print system calls and arguments similar to the 'strace' program
+(NOTE: the actual 'strace' program will not work because the user
+space emulator hasn't implemented ptrace).  At the moment this is
+incomplete.  All system calls that don't have a specific argument
+format are printed with information for six arguments.  Many
+flag-style arguments don't have decoders and will show up as numbers.
+
 @node Other binaries
 @subsection Other binaries
 
Index: qemu/linux-user/main.c
===================================================================
--- qemu.orig/linux-user/main.c	2007-12-11 19:02:01.000000000 -0700
+++ qemu/linux-user/main.c	2007-12-11 19:14:57.000000000 -0700
@@ -1943,7 +1943,12 @@
            "debug options:\n"
            "-d options   activate log (logfile=%s)\n"
            "-p pagesize  set the host page size to 'pagesize'\n"
-           "-strace      log system calls\n",
+           "-strace      log system calls\n"
+           "\n"
+           "environment variables:\n"
+           "QEMU_STRACE       Print system calls and arguments similar to the\n"
+           "                  'strace' program.  Enable by setting to any value.\n"
+           ,
            TARGET_ARCH,
            interp_prefix,
            x86_stack_size,