Add support for custom kernel headers

Change-Id: I39fe4de8919e59dd75e8cb535fa0648948035c26
diff --git a/minui/Android.mk b/minui/Android.mk
index 061bee6..5e42d2f 100644
--- a/minui/Android.mk
+++ b/minui/Android.mk
@@ -19,7 +19,11 @@
     LOCAL_ADDITIONAL_DEPENDENCIES := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr
     LOCAL_C_INCLUDES += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr/include
   else
-    LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
+    ifeq ($(TARGET_CUSTOM_KERNEL_HEADERS),)
+      LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
+    else
+      LOCAL_C_INCLUDES += $(TARGET_CUSTOM_KERNEL_HEADERS)
+    endif
   endif
 else
   LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
@@ -75,7 +79,11 @@
     LOCAL_ADDITIONAL_DEPENDENCIES := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr
     LOCAL_C_INCLUDES += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr/include
   else
-    LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
+    ifeq ($(TARGET_CUSTOM_KERNEL_HEADERS),)
+      LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
+    else
+      LOCAL_C_INCLUDES += $(TARGET_CUSTOM_KERNEL_HEADERS)
+    endif
   endif
 else
   LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minui/include
diff --git a/minuitwrp/Android.mk b/minuitwrp/Android.mk
index bc4e054..cf1eb5a 100644
--- a/minuitwrp/Android.mk
+++ b/minuitwrp/Android.mk
@@ -16,7 +16,11 @@
     LOCAL_ADDITIONAL_DEPENDENCIES := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr
     LOCAL_C_INCLUDES += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr/include
   else
-    LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minuitwrp/include
+    ifeq ($(TARGET_CUSTOM_KERNEL_HEADERS),)
+      LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minuitwrp/include
+    else
+      LOCAL_C_INCLUDES += $(TARGET_CUSTOM_KERNEL_HEADERS)
+    endif
   endif
 else
   LOCAL_C_INCLUDES += $(commands_recovery_local_path)/minuitwrp/include