diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 89ee5f2..4e2733f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -386,3 +386,18 @@ jobs:
         run: |
           cd $GITHUB_WORKSPACE
           make --debug test
+
+  openbsd:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: build + test
+        uses: vmactions/openbsd-vm@v1
+        with:
+          usesh: true
+          prepare: |
+            pkg_add cmake
+          run: |
+            cmake -B build
+            cmake --build build -j $(sysctl -n hw.ncpu)
+            ./build/qjs -qd
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d485cf0..7e4cbc4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -145,10 +145,7 @@ if(BUILD_QJS_LIBC)
     list(APPEND qjs_sources quickjs-libc.c)
 endif()
 list(APPEND qjs_defines _GNU_SOURCE)
-list(APPEND qjs_libs qjs)
-if(NOT WIN32)
-    list(APPEND qjs_libs dl)
-endif()
+list(APPEND qjs_libs qjs ${CMAKE_DL_LIBS})
 if(NOT MSVC)
     list(APPEND qjs_libs m pthread)
 endif()
diff --git a/qjs.c b/qjs.c
index 4bedc8b..47e207e 100644
--- a/qjs.c
+++ b/qjs.c
@@ -135,13 +135,10 @@ static inline size_t js_trace_malloc_usable_size(void *ptr)
     return malloc_size(ptr);
 #elif defined(_WIN32)
     return _msize(ptr);
-#elif defined(EMSCRIPTEN)
-    return 0;
 #elif defined(__linux__)
     return malloc_usable_size(ptr);
 #else
-    /* change this to `return 0;` if compilation fails */
-    return malloc_usable_size(ptr);
+    return 0;
 #endif
 }
 
@@ -257,13 +254,10 @@ static const JSMallocFunctions trace_mf = {
     malloc_size,
 #elif defined(_WIN32)
     (size_t (*)(const void *))_msize,
-#elif defined(EMSCRIPTEN)
-    NULL,
 #elif defined(__linux__) || defined(__CYGWIN__)
     (size_t (*)(const void *))malloc_usable_size,
 #else
-    /* change this to `NULL,` if compilation fails */
-    malloc_usable_size,
+    NULL,
 #endif
 };
 
diff --git a/quickjs-libc.c b/quickjs-libc.c
index 08eb00d..c871a16 100644
--- a/quickjs-libc.c
+++ b/quickjs-libc.c
@@ -73,12 +73,15 @@ typedef sig_t sighandler_t;
 #endif
 #endif /* __APPLE__ */
 
+#if defined(__OpenBSD__)
+typedef sig_t sighandler_t;
+extern char **environ;
 #endif
 
-#if !defined(_WIN32)
 /* enable the os.Worker API. IT relies on POSIX threads */
 #define USE_WORKER
-#endif
+
+#endif /* _WIN32 */
 
 #ifdef USE_WORKER
 #include <pthread.h>
@@ -3584,8 +3587,12 @@ void js_std_set_worker_new_context_func(JSContext *(*func)(JSRuntime *rt))
 #define OS_PLATFORM "js"
 #elif defined(__CYGWIN__)
 #define OS_PLATFORM "cygwin"
-#else
+#elif defined(__linux__)
 #define OS_PLATFORM "linux"
+#elif defined(__OpenBSD__)
+#define OS_PLATFORM "openbsd"
+#else
+#define OS_PLATFORM "unknown"
 #endif
 
 #define OS_FLAG(x) JS_PROP_INT32_DEF(#x, x, JS_PROP_CONFIGURABLE )
diff --git a/quickjs.c b/quickjs.c
index de9ad3e..956c05e 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -1646,13 +1646,10 @@ static inline size_t js_def_malloc_usable_size(void *ptr)
     return malloc_size(ptr);
 #elif defined(_WIN32)
     return _msize(ptr);
-#elif defined(EMSCRIPTEN)
-    return 0;
 #elif defined(__linux__)
     return malloc_usable_size(ptr);
 #else
-    /* change this to `return 0;` if compilation fails */
-    return malloc_usable_size(ptr);
+    return 0;
 #endif
 }
 
@@ -1720,13 +1717,10 @@ static const JSMallocFunctions def_malloc_funcs = {
     malloc_size,
 #elif defined(_WIN32)
     (size_t (*)(const void *))_msize,
-#elif defined(EMSCRIPTEN)
-    NULL,
 #elif defined(__linux__) || defined (__CYGWIN__)
     (size_t (*)(const void *))malloc_usable_size,
 #else
-    /* change this to `NULL,` if compilation fails */
-    malloc_usable_size,
+    NULL,
 #endif
 };