libpayload/lpgcc: Add more variables to support in-tree builds

Add $_DOTCONFIG and $_XCOMPILE pointing to the respective files and
use them.

Change-Id: I719b42d1c8abf055948daf5b000daa30cd249edd
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47630
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/payloads/libpayload/bin/lpgcc b/payloads/libpayload/bin/lpgcc
index 1e63d05..12d8e47 100755
--- a/payloads/libpayload/bin/lpgcc
+++ b/payloads/libpayload/bin/lpgcc
@@ -57,11 +57,17 @@
 # This will set the _LIBDIR and _INCDIR variables used below
 . $BASE/lp.functions
 
+if [ $_LIBDIR != $_OBJ ]; then
+	_DOTCONFIG=$BASE/../libpayload.config
+	_XCOMPILE=$BASE/../libpayload.xcompile
+else
+	_DOTCONFIG=$_OBJ/libpayload.config
+	_XCOMPILE=$_OBJ/xcompile
+fi
+
 # include libpayload config
-if [ -f $BASE/../libpayload.config ]; then
-	. $BASE/../libpayload.config
-elif [ -f $BASE/../.config ]; then
-	. $BASE/../.config
+if [ -f $_DOTCONFIG ]; then
+	. $_DOTCONFIG
 else
 	echo "Can't find config"
 	exit 1
@@ -174,8 +180,8 @@
 	    exit 1
     fi
 
-    if grep -q ARM64_A53_ERRATUM_843419=y $BASE/../libpayload.config &&
-       grep -q fix-cortex-a53-843419 $BASE/../libpayload.xcompile; then
+    if [ "$CONFIG_LP_ARM64_A53_ERRATUM_843419" = y ] &&
+       grep -q fix-cortex-a53-843419 $_XCOMPILE; then
             _LDFLAGS="$_LDFLAGS -Wl,--fix-cortex-a53-843419"
     fi