diff --git a/config/global/paths.in b/config/global/paths.in
index 39e15f35..b4e93ee0 100644
--- a/config/global/paths.in
+++ b/config/global/paths.in
@@ -42,7 +42,7 @@ config WORK_DIR
 
 config BUILD_TOP_DIR
     string
-    default "${CT_WORK_DIR}/${CT_HOST:+HOST-${CT_HOST}/}${CT_TARGET}"
+    default "${CT_WORK_DIR:-${CT_TOP_DIR}/.build}/${CT_HOST:+HOST-${CT_HOST}/}${CT_TARGET}"
 
 config PREFIX_DIR
     string
diff --git a/scripts/crosstool-NG.sh b/scripts/crosstool-NG.sh
index 7909438a..fb6856e1 100644
--- a/scripts/crosstool-NG.sh
+++ b/scripts/crosstool-NG.sh
@@ -74,6 +74,7 @@ for d in            \
     LOCAL_TARBALLS  \
     WORK            \
     PREFIX          \
+    BUILD_TOP       \
     INSTALL         \
     ; do
         eval dir="\${CT_${d}_DIR}"
@@ -88,6 +89,17 @@ for d in            \
                 CT_Abort "'CT_${d}_DIR'='${dir}' contains a comma in it.\nDon't use commas in paths, it breaks things."
                 ;;
         esac
+        case "${dir}" in
+            /*)
+                # Absolute path, okay
+                ;;
+            *)
+                # Relative path from CT_TOP_DIR, make absolute
+                eval CT_${d}_DIR="${CT_TOP_DIR}/${dir}"
+                # Having .. inside CT_PREFIX breaks relocatability.
+                CT_SanitizeVarDir CT_${d}_DIR
+                ;;
+        esac
 done
 
 # Where will we work?
@@ -315,9 +327,6 @@ CT_DoExecLog DEBUG rm -f "${CT_PREFIX_DIR}/foo"
 
 # Setting up the rest of the environment only if not restarting
 if [ -z "${CT_RESTART}" ]; then
-    # Having .. inside CT_PREFIX breaks relocatability.
-    CT_SanitizeVarDir CT_PREFIX_DIR
-
     case "${CT_SYSROOT_NAME}" in
         "")     CT_SYSROOT_NAME="sysroot";;
         .)      CT_Abort "Sysroot name is set to '.' which is forbidden";;