diff --git a/bootstrap-carla.sh b/bootstrap-carla.sh
index 0f69f15..47c3961 100755
--- a/bootstrap-carla.sh
+++ b/bootstrap-carla.sh
@@ -192,7 +192,7 @@ function build_pyqt() {
 # file/magic (posix only)
 
 if [ "${WIN32}" -eq 0 ]; then
-    download file "${FILE_VERSION}" "ftp://ftp.astron.com/pub/file"
+    download file "${FILE_VERSION}" "${FILE_URL}"
     build_autoconf file "${FILE_VERSION}"
 fi
 
@@ -200,7 +200,7 @@ fi
 # libffi (for python, not needed in macOS)
 
 if [ "${MACOS}" -eq 0 ]; then
-    download libffi "${LIBFFI_VERSION}" "https://sourceware.org/pub/libffi"
+    download libffi "${LIBFFI_VERSION}" "${LIBFFI_URL}"
     build_autoconf libffi "${LIBFFI_VERSION}"
 fi
 
diff --git a/bootstrap-jack2.sh b/bootstrap-jack2.sh
index 833993a..639d8fe 100755
--- a/bootstrap-jack2.sh
+++ b/bootstrap-jack2.sh
@@ -72,11 +72,6 @@ function build_custom_db() {
         extraconfrules+=" --enable-mingw"
     fi
 
-    # TODO jack2 cannot be built with LTO right now
-    export EXTRA_CFLAGS="-fno-lto"
-    export EXTRA_CXXFLAGS="-fno-lto"
-    export EXTRA_LDFLAGS="-fno-lto"
-
     _prebuild "${name}" "${pkgdir}"
 
     if [ ! -f "${pkgdir}/.stamp_configured" ]; then
@@ -148,11 +143,6 @@ fi
 # tre (win32 only)
 
 if [ "${WIN32}" -eq 1 ]; then
-    # TODO jack2 cannot be built with LTO right now
-    export EXTRA_CFLAGS="-fno-lto"
-    export EXTRA_CXXFLAGS="-fno-lto"
-    export EXTRA_LDFLAGS="-fno-lto"
-
     download tre "${TRE_VERSION}" "${TRE_URL}" "" "git"
     build_autoconfgen tre "${TRE_VERSION}" "--disable-nls"
 fi
@@ -169,11 +159,6 @@ if [ "${WIN64}" -eq 1 ]; then
     PAWPAW_PREFIX="${PAWPAW_DIR}/targets/win64"
     source setup/functions.sh
 
-    # TODO jack2 cannot be built with LTO right now
-    export EXTRA_CFLAGS="-fno-lto"
-    export EXTRA_CXXFLAGS="-fno-lto"
-    export EXTRA_LDFLAGS="-fno-lto"
-
     copy_download tre tre-x32 "${TRE_VERSION}"
     build_autoconfgen tre-x32 "${TRE_VERSION}" "--disable-nls --libdir=${PAWPAW_PREFIX}/lib32"
 
diff --git a/setup/env.sh b/setup/env.sh
index b1ee38d..32987be 100644
--- a/setup/env.sh
+++ b/setup/env.sh
@@ -53,10 +53,14 @@ PAWPAW_TMPDIR="/tmp"
 ## build flags
 
 BUILD_FLAGS="-O2 -pipe -I${PAWPAW_PREFIX}/include ${EXTRA_FLAGS}"
-BUILD_FLAGS+=" -ffast-math -fno-strict-aliasing -flto"
+BUILD_FLAGS+=" -ffast-math"
 BUILD_FLAGS+=" -fPIC -DPIC -DNDEBUG -D_FORTIFY_SOURCE=2"
 BUILD_FLAGS+=" -fdata-sections -ffunction-sections -fno-common -fstack-protector -fvisibility=hidden"
 
+if [ "${PAWPAW_SKIP_LTO}" -eq 1 ]; then
+    BUILD_FLAGS+=" -fno-strict-aliasing -flto"
+fi
+
 if [ "${TOOLCHAIN_PREFIX}" = "arm-linux-gnueabihf" ]; then
     BUILD_FLAGS+=" -mfpu=neon-vfpv4 -mfloat-abi=hard"
 elif [ "${TOOLCHAIN_PREFIX}" != "aarch64-linux-gnu" ]; then