build: add option --enable-host-bios

Add option to enable building in support for the host bios.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I324fc071f07cd364fd39c7df1ccfd9f0fd509a46
diff --git a/bmc/Makefile.am b/bmc/Makefile.am
index 6378ffb..8ada86b 100644
--- a/bmc/Makefile.am
+++ b/bmc/Makefile.am
@@ -5,6 +5,12 @@
 	phosphor-ipmi-flash-bmc-prepare.target \
 	phosphor-ipmi-flash-bmc-verify.target \
 	phosphor-ipmi-flash-bmc-update.target
+if ENABLE_HOST_BIOS
+systemdsystemunit_DATA += \
+	phosphor-ipmi-flash-bios-prepare.target \
+	phosphor-ipmi-flash-bios-verify.target \
+	phosphor-ipmi-flash-bios-update.target
+endif
 endif
 
 noinst_LTLIBRARIES = libfirmwareblob_common.la