Fix out-of-tree builds

Since b16df9ee5f3b out-of-tree builds have been broken because we
started validating the newly user-configurable $erratatxt file
before linking it into the build dir. We fix this not by moving
the validation, but by removing the linking and instead using the
full path of the $erratatxt file. This allows one to keep that file
separate from the src and build dirs.

Fixes: b16df9ee5f3b ("arch-run: Add reserved variables to the default environ")
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20200511070641.23492-1-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/configure b/configure
index 5d2cd90..f9d030f 100755
--- a/configure
+++ b/configure
@@ -17,7 +17,7 @@
 u32_long=
 vmm="qemu"
 errata_force=0
-erratatxt="errata.txt"
+erratatxt="$srcdir/errata.txt"
 
 usage() {
     cat <<-EOF
@@ -89,7 +89,8 @@
 	    environ_default=no
 	    ;;
 	--erratatxt)
-	    erratatxt="$arg"
+	    erratatxt=
+	    [ "$arg" ] && erratatxt=$(eval realpath "$arg")
 	    ;;
 	--help)
 	    usage
@@ -169,9 +170,6 @@
 
     echo "linking scripts..."
     ln -sf "$srcdir/scripts"
-
-    echo "linking errata.txt..."
-    ln -sf "$srcdir/errata.txt"
 fi
 
 # link lib/asm for the architecture