diff --git a/PKGBUILD b/PKGBUILD
index 482fb12..6f27162 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -19,6 +19,7 @@ makedepends=(
   cmake
   git
   ninja
+  python
 )
 provides=(
   libmbedcrypto.so
@@ -38,6 +39,12 @@ pkgver() {
   git describe --tags | sed 's/^v//; s/^mbedtls-//'
 }
 
+prepare() {
+  cd mbedtls
+  scripts/config.py set MBEDTLS_THREADING_C
+  scripts/config.py set MBEDTLS_THREADING_PTHREAD
+}
+
 build() {
   export CFLAGS+=' -ffat-lto-objects'
   cmake -S mbedtls -B build -G Ninja \