diff --git a/build_tools/build_detect_platform b/build_tools/build_detect_platform
index f051ec44f..c2749c1f1 100755
--- a/build_tools/build_detect_platform
+++ b/build_tools/build_detect_platform
@@ -31,9 +31,9 @@ fi
 # Default to fbcode gcc on internal fb machines
 if [ -d /mnt/gvfs/third-party -a -z "$CXX" ]; then
     if [ -z "$USE_CLANG" ]; then
-        source fbcode.gcc471.sh
+        ./source fbcode.gcc471.sh
     else
-        source fbcode.clang31.sh
+        ./source fbcode.clang31.sh
     fi
 fi