diff --git a/metadata.json b/metadata.json
index 5a7e0e6..30c78b5 100644
--- a/metadata.json
+++ b/metadata.json
@@ -27,7 +27,7 @@
     "capabilities": [],
     "nix": {
         "packages": {
-            "runtime": ["postgresql", "nlohmann_json"]
+            "runtime": ["libpq", "nlohmann_json"]
         },
         "external_libraries": [
             {
diff --git a/src/delivery_module_plugin.cpp b/src/delivery_module_plugin.cpp
index 74e129e..5a816d3 100644
--- a/src/delivery_module_plugin.cpp
+++ b/src/delivery_module_plugin.cpp
@@ -1,4 +1,5 @@
 #include "delivery_module_plugin.h"
+#include <chrono>
 #include <cstdio>
 #include <ctime>
 #include <memory>
@@ -34,9 +35,13 @@ std::vector<uint8_t> base64Decode(const std::string& encoded) {
 }
 
 int64_t currentTimestampNs() {
-    struct timespec ts;
-    clock_gettime(CLOCK_REALTIME, &ts);
-    return static_cast<int64_t>(ts.tv_sec) * 1000000000LL + static_cast<int64_t>(ts.tv_nsec);
+    // std::chrono rather than clock_gettime(CLOCK_REALTIME): the POSIX call is
+    // not available on mingw (neither the function nor CLOCK_REALTIME is
+    // declared), which broke the Windows cross-build. system_clock is the
+    // portable spelling of the same wall-clock reading.
+    return std::chrono::duration_cast<std::chrono::nanoseconds>(
+               std::chrono::system_clock::now().time_since_epoch())
+        .count();
 }
 } // namespace