diff --git a/mypyc/lib-rt/byteswriter_extra_ops.c b/mypyc/lib-rt/byteswriter_extra_ops.c
index 03827bf54fea..2a5b13c0d7c9 100644
--- a/mypyc/lib-rt/byteswriter_extra_ops.c
+++ b/mypyc/lib-rt/byteswriter_extra_ops.c
@@ -3,6 +3,8 @@
 
 #include "byteswriter_extra_ops.h"
 
+#ifdef MYPYC_EXPERIMENTAL
+
 char CPyBytesWriter_Write(PyObject *obj, PyObject *value) {
     BytesWriterObject *self = (BytesWriterObject *)obj;
     const char *data;
@@ -29,3 +31,5 @@ char CPyBytesWriter_Write(PyObject *obj, PyObject *value) {
     self->len += size;
     return CPY_NONE;
 }
+
+#endif // MYPYC_EXPERIMENTAL
diff --git a/mypyc/lib-rt/byteswriter_extra_ops.h b/mypyc/lib-rt/byteswriter_extra_ops.h
index 09cd018d4e5f..885dfe082624 100644
--- a/mypyc/lib-rt/byteswriter_extra_ops.h
+++ b/mypyc/lib-rt/byteswriter_extra_ops.h
@@ -1,6 +1,11 @@
 #ifndef BYTESWRITER_EXTRA_OPS_H
 #define BYTESWRITER_EXTRA_OPS_H
 
+#ifdef MYPYC_EXPERIMENTAL
+
+#include <stdint.h>
+#include <Python.h>
+
 #include "librt_strings.h"
 
 static inline CPyTagged
@@ -31,4 +36,6 @@ CPyBytesWriter_Append(PyObject *obj, uint8_t value) {
 
 char CPyBytesWriter_Write(PyObject *obj, PyObject *value);
 
+#endif // MYPYC_EXPERIMENTAL
+
 #endif
diff --git a/mypyc/lib-rt/function_wrapper.c b/mypyc/lib-rt/function_wrapper.c
index 8348168776c2..f195d10359e5 100644
--- a/mypyc/lib-rt/function_wrapper.c
+++ b/mypyc/lib-rt/function_wrapper.c
@@ -33,7 +33,6 @@ static PyObject* CPyFunction_repr(CPyFunction *op) {
 }
 
 static PyObject* CPyFunction_call(PyObject *func, PyObject *args, PyObject *kw) {
-    PyObject *result;
     CPyFunction *f = (CPyFunction *)func;
     vectorcallfunc vc = CPyFunction_func_vectorcall(f);
     assert(vc);
diff --git a/mypyc/lib-rt/getargs.c b/mypyc/lib-rt/getargs.c
index 163b9ac2b163..6eb4f750804a 100644
--- a/mypyc/lib-rt/getargs.c
+++ b/mypyc/lib-rt/getargs.c
@@ -437,7 +437,7 @@ static void
 skipitem(const char **p_format, va_list *p_va)
 {
     const char *format = *p_format;
-    char c = *format++;
+    format++;
 
     if (p_va != NULL) {
         (void) va_arg(*p_va, PyObject **);
diff --git a/mypyc/lib-rt/librt_base64.h b/mypyc/lib-rt/librt_base64.h
index fedfefd9a38a..122e4d6a3bc3 100644
--- a/mypyc/lib-rt/librt_base64.h
+++ b/mypyc/lib-rt/librt_base64.h
@@ -12,6 +12,8 @@ import_librt_base64(void)
 
 #else  // MYPYC_EXPERIMENTAL
 
+#include <Python.h>
+
 #define LIBRT_BASE64_ABI_VERSION 1
 #define LIBRT_BASE64_API_VERSION 2
 #define LIBRT_BASE64_API_LEN 4
diff --git a/mypyc/lib-rt/librt_internal.h b/mypyc/lib-rt/librt_internal.h
index 501162a27980..1b325b20d95b 100644
--- a/mypyc/lib-rt/librt_internal.h
+++ b/mypyc/lib-rt/librt_internal.h
@@ -1,6 +1,8 @@
 #ifndef LIBRT_INTERNAL_H
 #define LIBRT_INTERNAL_H
 
+#include <Python.h>
+
 // ABI version -- only an exact match is compatible. This will only be changed in
 // very exceptional cases (likely never) due to strict backward compatibility
 // requirements.
diff --git a/mypyc/lib-rt/librt_strings.h b/mypyc/lib-rt/librt_strings.h
index e619435f5292..4069b70ceb43 100644
--- a/mypyc/lib-rt/librt_strings.h
+++ b/mypyc/lib-rt/librt_strings.h
@@ -12,6 +12,8 @@ import_librt_strings(void)
 
 #else  // MYPYC_EXPERIMENTAL
 
+#include <Python.h>
+
 // ABI version -- only an exact match is compatible. This will only be changed in
 // very exceptional cases (likely never) due to strict backward compatibility
 // requirements.