diff --git a/Makefile b/Makefile
index 7b3ec75b..da7a1fb6 100644
--- a/Makefile
+++ b/Makefile
@@ -83,8 +83,14 @@ distclean:
 stats: $(QJS)
 	$(QJS) -qd
 
-# implicitly .PHONY because it doesn't generate output
-cxxtest: CXXFLAGS+=-std=c++11 -fsyntax-only -Wall -Wextra -Werror -Wno-unused-parameter
+# effectively .PHONY because it doesn't generate output
+ctest: CFLAGS=-std=c11 -fsyntax-only -Wall -Wextra -Werror -pedantic
+ctest: ctest.c quickjs.h
+	$(CC) $(CFLAGS) -DJS_NAN_BOXING=0 $<
+	$(CC) $(CFLAGS) -DJS_NAN_BOXING=1 $<
+
+# effectively .PHONY because it doesn't generate output
+cxxtest: CXXFLAGS=-std=c++11 -fsyntax-only -Wall -Wextra -Werror -pedantic
 cxxtest: cxxtest.cc quickjs.h
 	$(CXX) $(CXXFLAGS) -DJS_NAN_BOXING=0 $<
 	$(CXX) $(CXXFLAGS) -DJS_NAN_BOXING=1 $<
@@ -116,4 +122,4 @@ unicode_gen: $(BUILD_DIR)
 libunicode-table.h: unicode_gen
 	$(BUILD_DIR)/unicode_gen unicode $@
 
-.PHONY: all cxxtest debug fuzz install clean codegen distclean stats test test262 test262-update test262-check microbench unicode_gen $(QJS) $(QJSC)
+.PHONY: all ctest cxxtest debug fuzz install clean codegen distclean stats test test262 test262-update test262-check microbench unicode_gen $(QJS) $(QJSC)
diff --git a/ctest.c b/ctest.c
new file mode 100644
index 00000000..eeb03e86
--- /dev/null
+++ b/ctest.c
@@ -0,0 +1,17 @@
+// note: file is not actually compiled, only checked for C syntax errors
+#include "quickjs.h"
+
+int main(void)
+{
+    JSRuntime *rt = JS_NewRuntime();
+    JSContext *ctx = JS_NewContext(rt);
+    JS_FreeValue(ctx, JS_NAN);
+    JS_FreeValue(ctx, JS_UNDEFINED);
+    JS_FreeValue(ctx, JS_NewFloat64(ctx, 42));
+    // not a legal way of using JS_MKPTR but this is here
+    // to have the compiler syntax-check its definition
+    JS_FreeValue(ctx, JS_MKPTR(JS_TAG_UNINITIALIZED, 0));
+    JS_FreeContext(ctx);
+    JS_FreeRuntime(rt);
+    return 0;
+}
diff --git a/cxxtest.cc b/cxxtest.cc
index 6488533d..b6151009 100644
--- a/cxxtest.cc
+++ b/cxxtest.cc
@@ -1,17 +1,2 @@
 // note: file is not actually compiled, only checked for C++ syntax errors
-#include "quickjs.h"
-
-int main(void)
-{
-    JSRuntime *rt = JS_NewRuntime();
-    JSContext *ctx = JS_NewContext(rt);
-    JS_FreeValue(ctx, JS_NAN);
-    JS_FreeValue(ctx, JS_UNDEFINED);
-    JS_FreeValue(ctx, JS_NewFloat64(ctx, 42));
-    // not a legal way of using JS_MKPTR but this is here
-    // to have the compiler syntax-check its definition
-    JS_FreeValue(ctx, JS_MKPTR(JS_TAG_UNINITIALIZED, 0));
-    JS_FreeContext(ctx);
-    JS_FreeRuntime(rt);
-    return 0;
-}
+#include "ctest.c"
diff --git a/quickjs.h b/quickjs.h
index 12111f80..f08a85c6 100644
--- a/quickjs.h
+++ b/quickjs.h
@@ -514,21 +514,25 @@ JS_EXTERN int JS_IsRegisteredClass(JSRuntime *rt, JSClassID class_id);
 
 static js_force_inline JSValue JS_NewBool(JSContext *ctx, JS_BOOL val)
 {
+    (void)&ctx;
     return JS_MKVAL(JS_TAG_BOOL, (val != 0));
 }
 
 static js_force_inline JSValue JS_NewInt32(JSContext *ctx, int32_t val)
 {
+    (void)&ctx;
     return JS_MKVAL(JS_TAG_INT, val);
 }
 
 static js_force_inline JSValue JS_NewFloat64(JSContext *ctx, double val)
 {
+    (void)&ctx;
     return __JS_NewFloat64(val);
 }
 
 static js_force_inline JSValue JS_NewCatchOffset(JSContext *ctx, int32_t val)
 {
+    (void)&ctx;
     return JS_MKVAL(JS_TAG_CATCH_OFFSET, val);
 }
 
@@ -566,8 +570,8 @@ static inline JS_BOOL JS_IsNumber(JSValue v)
 
 static inline JS_BOOL JS_IsBigInt(JSContext *ctx, JSValue v)
 {
-    int tag = JS_VALUE_GET_TAG(v);
-    return tag == JS_TAG_BIG_INT;
+    (void)&ctx;
+    return JS_VALUE_GET_TAG(v) == JS_TAG_BIG_INT;
 }
 
 static inline JS_BOOL JS_IsBool(JSValue v)