Allow IKHEADERS to be either =y or =m

There will be no immutable GKI modules for the R release.
Vendors may have the option to enable IKHEADERS as a module
for non GKI builds.

5.4 is allowed only as a GKI. Note the difference in configuration
for IKHEADERS between 5.4 and 4.14/4.19.

Bug: 143488798
Test: Treehugger
Change-Id: I775b6cf0122d69345ee6d7f06561d0ffb6316559
diff --git a/android-4.14/android-base-conditional.xml b/android-4.14/android-base-conditional.xml
index a87cfe4..ada11e7 100644
--- a/android-4.14/android-base-conditional.xml
+++ b/android-4.14/android-base-conditional.xml
@@ -113,3 +113,17 @@
 	</config>
 </group>
 
+<!-- CONFIG_IKHEADERS=y || CONFIG_IKHEADERS=m -->
+<group>
+	<conditions>
+		<config>
+			<key>CONFIG_IKHEADERS</key>
+			<value type="tristate">n</value>
+		</config>
+	</conditions>
+	<config>
+		<key>DISALLOW_CONFIG_IKHEADERS_IS_N</key>
+		<value type="bool">y</value>
+	</config>
+</group>
+
diff --git a/android-4.14/android-base.config b/android-4.14/android-base.config
index 5ec53da..cc1149c 100644
--- a/android-4.14/android-base.config
+++ b/android-4.14/android-base.config
@@ -58,7 +58,6 @@
 CONFIG_HIGH_RES_TIMERS=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
-CONFIG_IKHEADERS=m
 CONFIG_INET6_ESP=y
 CONFIG_INET6_IPCOMP=y
 CONFIG_INET6_XFRM_MODE_TRANSPORT=y
diff --git a/android-4.19/android-base-conditional.xml b/android-4.19/android-base-conditional.xml
index 14e6cdb..3bc4d5c 100644
--- a/android-4.19/android-base-conditional.xml
+++ b/android-4.19/android-base-conditional.xml
@@ -113,3 +113,17 @@
 	</config>
 </group>
 
+<!-- CONFIG_IKHEADERS=y || CONFIG_IKHEADERS=m -->
+<group>
+	<conditions>
+		<config>
+			<key>CONFIG_IKHEADERS</key>
+			<value type="tristate">n</value>
+		</config>
+	</conditions>
+	<config>
+		<key>DISALLOW_CONFIG_IKHEADERS_IS_N</key>
+		<value type="bool">y</value>
+	</config>
+</group>
+
diff --git a/android-4.19/android-base.config b/android-4.19/android-base.config
index 503458c..1c286e9 100644
--- a/android-4.19/android-base.config
+++ b/android-4.19/android-base.config
@@ -58,7 +58,6 @@
 CONFIG_HIGH_RES_TIMERS=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
-CONFIG_IKHEADERS=m
 CONFIG_INET6_ESP=y
 CONFIG_INET6_IPCOMP=y
 CONFIG_INET6_XFRM_MODE_TRANSPORT=y
diff --git a/android-5.4/android-base-conditional.xml b/android-5.4/android-base-conditional.xml
index 059149d..b10ad3b 100644
--- a/android-5.4/android-base-conditional.xml
+++ b/android-5.4/android-base-conditional.xml
@@ -113,3 +113,17 @@
 	</config>
 </group>
 
+<!-- CONFIG_IKHEADERS=y || CONFIG_IKHEADERS=m -->
+<group>
+	<conditions>
+		<config>
+			<key>CONFIG_IKHEADERS</key>
+			<value type="tristate">n</value>
+		</config>
+	</conditions>
+	<config>
+		<key>DISALLOW_CONFIG_IKHEADERS_IS_N</key>
+		<value type="bool">y</value>
+	</config>
+</group>
+
diff --git a/android-5.4/android-base.config b/android-5.4/android-base.config
index 7d135ec..e819f00 100644
--- a/android-5.4/android-base.config
+++ b/android-5.4/android-base.config
@@ -58,7 +58,6 @@
 CONFIG_HIGH_RES_TIMERS=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
-CONFIG_IKHEADERS=m
 CONFIG_INET6_ESP=y
 CONFIG_INET6_IPCOMP=y
 CONFIG_INET=y