Add new command line option -singlestep for tcg single stepping.

This replaces a compile time option for some targets and adds
this feature to targets which did not have a compile time option.

Add monitor command to enable or disable single step mode.

Modify monitor command "info status" to display single step mode.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7004 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/linux-user/main.c b/linux-user/main.c
index feb3036..3b9dfc7 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -39,6 +39,8 @@
 
 char *exec_path;
 
+int singlestep;
+
 static const char *interp_prefix = CONFIG_QEMU_PREFIX;
 const char *qemu_uname_release = CONFIG_UNAME_RELEASE;
 
@@ -2217,6 +2219,7 @@
            "Debug options:\n"
            "-d options   activate log (logfile=%s)\n"
            "-p pagesize  set the host page size to 'pagesize'\n"
+           "-singlestep  always run in singlestep mode\n"
            "-strace      log system calls\n"
            "\n"
            "Environment variables:\n"
@@ -2359,6 +2362,8 @@
             }
         } else if (!strcmp(r, "drop-ld-preload")) {
             (void) envlist_unsetenv(envlist, "LD_PRELOAD");
+        } else if (!strcmp(r, "singlestep")) {
+            singlestep = 1;
         } else if (!strcmp(r, "strace")) {
             do_strace = 1;
         } else