diff --git a/core/src/main/resources/org/teavm/backend/c/core.h b/core/src/main/resources/org/teavm/backend/c/core.h
index f706f6dc2..06a2602a0 100644
--- a/core/src/main/resources/org/teavm/backend/c/core.h
+++ b/core/src/main/resources/org/teavm/backend/c/core.h
@@ -5,6 +5,7 @@
 #include "definitions.h"
 #include "heapdump.h"
 #include "memory.h"
+#include <stdlib.h>
 
 #if TEAVM_MEMORY_TRACE
     #include "heaptrace.h"
diff --git a/core/src/main/resources/org/teavm/backend/c/fiber.c b/core/src/main/resources/org/teavm/backend/c/fiber.c
index 26adb3ede..02d52639c 100644
--- a/core/src/main/resources/org/teavm/backend/c/fiber.c
+++ b/core/src/main/resources/org/teavm/backend/c/fiber.c
@@ -1,5 +1,8 @@
 #include "fiber.h"
 #include "definitions.h"
+#include <stddef.h>
+#include <locale.h>
+#include <time.h>
 
 #if TEAVM_UNIX
     #include <signal.h>
diff --git a/core/src/main/resources/org/teavm/backend/c/file.c b/core/src/main/resources/org/teavm/backend/c/file.c
index 55cdd735f..dad0fbe31 100644
--- a/core/src/main/resources/org/teavm/backend/c/file.c
+++ b/core/src/main/resources/org/teavm/backend/c/file.c
@@ -1,6 +1,7 @@
 #include "file.h"
 #include "string.h"
 #include "time.h"
+#include "date.h"
 #include "definitions.h"
 #include <stdlib.h>
 #include <errno.h>
diff --git a/core/src/main/resources/org/teavm/backend/c/log.c b/core/src/main/resources/org/teavm/backend/c/log.c
index e1fa32f0a..deb574f11 100644
--- a/core/src/main/resources/org/teavm/backend/c/log.c
+++ b/core/src/main/resources/org/teavm/backend/c/log.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <inttypes.h>
+#include <wchar.h>
 
 #if TEAVM_WINDOWS
     #include <Windows.h>
diff --git a/core/src/main/resources/org/teavm/backend/c/memory.c b/core/src/main/resources/org/teavm/backend/c/memory.c
index 902b794d4..811681031 100644
--- a/core/src/main/resources/org/teavm/backend/c/memory.c
+++ b/core/src/main/resources/org/teavm/backend/c/memory.c
@@ -1,6 +1,7 @@
 #include "memory.h"
 #include "definitions.h"
 #include <stdlib.h>
+#include <string.h>
 
 #if TEAVM_UNIX
     #include <unistd.h>
diff --git a/core/src/main/resources/org/teavm/backend/c/time.c b/core/src/main/resources/org/teavm/backend/c/time.c
index c5a5fb40c..26808f4d1 100644
--- a/core/src/main/resources/org/teavm/backend/c/time.c
+++ b/core/src/main/resources/org/teavm/backend/c/time.c
@@ -1,6 +1,7 @@
 #include "time.h"
 #include "definitions.h"
 #include <time.h>
+#include <math.h>
 
 #if TEAVM_WINDOWS
     #include <Windows.h>
diff --git a/core/src/main/resources/org/teavm/backend/c/virtcall.c b/core/src/main/resources/org/teavm/backend/c/virtcall.c
index 66419241a..a2acee027 100644
--- a/core/src/main/resources/org/teavm/backend/c/virtcall.c
+++ b/core/src/main/resources/org/teavm/backend/c/virtcall.c
@@ -1,4 +1,3 @@
-#pragma once
 #include "virtcall.h"
 #include "definitions.h"
 #include <stdlib.h>