Add compile option to disable safe mode option in boot flags

Some platforms doe not support safe mode in
set/get system boot options commands, add an compile option to disable it.
Using the below command:
./configure  --disable-boot-flag-safe-mode-support

Tested:
After adding this compile option, below command fails:

// set safe mode in set system boot options command
ipmitool raw 0 8 5 0x80 0xc
Unable to send RAW command (channel=0x0 netfn=0x0 lun=0x0 cmd=0x8 rsp=0xcc):
Invalid data field in request

Signed-off-by: Yong Li <yong.b.li@linux.intel.com>
Change-Id: Ie479a0c68a8e9fc79f99c9d4cc10cdd1e6ceb20e
diff --git a/configure.ac b/configure.ac
index 04c48b8..296165f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,6 +25,17 @@
 AC_PROG_INSTALL
 AC_PROG_MAKE_SET
 
+# Add an option to enable/disable safe mode in boot flags
+AC_ARG_ENABLE([boot-flag-safe-mode-support],
+    AS_HELP_STRING([--disable-boot-flag-safe-mode-support], [Disable safe mode option in boot flags. [default=enable]])
+)
+AS_IF([test "x$enable_boot_flag_safe_mode_support" != "xno"],
+    AC_MSG_NOTICE([Enabling safe mode option in boot flags])
+    [cpp_flags="-DENABLE_BOOT_FLAG_SAFE_MODE_SUPPORT"]
+    AC_SUBST([CPPFLAGS], [$cpp_flags]),
+    AC_MSG_WARN([Disabling safe mode option in boot flags])
+)
+
 # Add an option to enable/disable i2c master write read command white list checking
 AC_ARG_ENABLE([i2c-whitelist-check],
     AS_HELP_STRING([--disable-i2c-whitelist-check], [Disable I2C master write read command white list check. [default=enable]])