diff --git a/configure b/configure
index 30d53da4837..d53583dfbcb 100755
--- a/configure
+++ b/configure
@@ -5408,6 +5408,30 @@ rm -f core conftest.err conftest.$ac_objext \
     CFLAGS="$CFLAGS -marm -mfloat-abi=$float_abi"
     TARGETFLAGS="-marm -mfloat-abi=$float_abi"
 
+    ;;
+  aarch64*)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports __builtin_ms_va_list" >&5
+$as_echo_n "checking whether $CC supports __builtin_ms_va_list... " >&6; }
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdarg.h>
+int
+main ()
+{
+void func(__builtin_ms_va_list *args);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+                       as_fn_error $? "You need clang >= 5.0 to build Wine for arm64." "$LINENO" 5
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
     ;;
   i[3456789]86*)
     enable_win16=${enable_win16:-yes}
diff --git a/configure.ac b/configure.ac
index 54c31d86c8f..b4a8ef0d13b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -205,6 +205,13 @@ case $host in
     CFLAGS="$CFLAGS -marm -mfloat-abi=$float_abi"
     AC_SUBST(TARGETFLAGS,"-marm -mfloat-abi=$float_abi")
     ;;
+  aarch64*)
+    AC_MSG_CHECKING([whether $CC supports __builtin_ms_va_list])
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdarg.h>]], [[void func(__builtin_ms_va_list *args);]])],
+                      [AC_MSG_RESULT([yes])],
+                      [AC_MSG_RESULT([no])
+                       AC_MSG_ERROR([You need clang >= 5.0 to build Wine for arm64.])])
+    ;;
   i[[3456789]]86*)
     enable_win16=${enable_win16:-yes}
     ;;
diff --git a/include/msvcrt/crtdefs.h b/include/msvcrt/crtdefs.h
index a9edef57c4f..0c0b08748ea 100644
--- a/include/msvcrt/crtdefs.h
+++ b/include/msvcrt/crtdefs.h
@@ -62,6 +62,8 @@
 #  endif
 # elif defined(__arm__) && defined (__GNUC__) && !defined(__SOFTFP__)
 #   define __stdcall __attribute__((pcs("aapcs-vfp")))
+# elif defined(__aarch64__) && defined (__GNUC__)
+#  define __stdcall __attribute__((ms_abi))
 # else  /* __i386__ */
 #  define __stdcall
 # endif  /* __i386__ */
@@ -82,13 +84,15 @@
 #  endif
 # elif defined(__arm__) && defined (__GNUC__) && !defined(__SOFTFP__)
 #   define __cdecl __attribute__((pcs("aapcs-vfp")))
+# elif defined(__aarch64__) && defined (__GNUC__)
+#  define __cdecl __attribute__((ms_abi))
 # elif !defined(_MSC_VER)
 #  define __cdecl
 # endif
 #endif /* __cdecl */
 
 #ifndef __ms_va_list
-# if defined(__x86_64__) && defined (__GNUC__)
+# if (defined(__x86_64__) || defined(__aarch64__)) && defined (__GNUC__)
 #  define __ms_va_list __builtin_ms_va_list
 #  define __ms_va_start(list,arg) __builtin_ms_va_start(list,arg)
 #  define __ms_va_end(list) __builtin_ms_va_end(list)
diff --git a/include/windef.h b/include/windef.h
index 40028f3373c..8e8a08afbbf 100644
--- a/include/windef.h
+++ b/include/windef.h
@@ -71,6 +71,8 @@ extern "C" {
 #  endif
 # elif defined(__arm__) && defined (__GNUC__) && !defined(__SOFTFP__)
 #   define __stdcall __attribute__((pcs("aapcs-vfp")))
+# elif defined(__aarch64__) && defined (__GNUC__)
+#  define __stdcall __attribute__((ms_abi))
 # else  /* __i386__ */
 #  define __stdcall
 # endif  /* __i386__ */
@@ -91,13 +93,15 @@ extern "C" {
 #  endif
 # elif defined(__arm__) && defined (__GNUC__) && !defined(__SOFTFP__)
 #   define __cdecl __attribute__((pcs("aapcs-vfp")))
+# elif defined(__aarch64__) && defined (__GNUC__)
+#  define __cdecl __attribute__((ms_abi))
 # elif !defined(_MSC_VER)
 #  define __cdecl
 # endif
 #endif /* __cdecl */
 
 #ifndef __ms_va_list
-# if defined(__x86_64__) && defined (__GNUC__)
+# if (defined(__x86_64__) || defined(__aarch64__)) && defined (__GNUC__)
 #  define __ms_va_list __builtin_ms_va_list
 #  define __ms_va_start(list,arg) __builtin_ms_va_start(list,arg)
 #  define __ms_va_end(list) __builtin_ms_va_end(list)
diff --git a/include/wine/test.h b/include/wine/test.h
index 21e2ac76d5f..e3e4bcf77b7 100644
--- a/include/wine/test.h
+++ b/include/wine/test.h
@@ -90,7 +90,7 @@ static inline int winetest_strcmpW( const WCHAR *str1, const WCHAR *str2 )
 #define START_TEST(name) void func_##name(void)
 #endif
 
-#if defined(__x86_64__) && defined(__GNUC__) && defined(__WINE_USE_MSVCRT)
+#if (defined(__x86_64__) || defined(__aarch64__)) && defined(__GNUC__) && defined(__WINE_USE_MSVCRT)
 #define __winetest_cdecl __cdecl
 #define __winetest_va_list __builtin_ms_va_list
 #else
@@ -181,7 +181,7 @@ extern void __winetest_cdecl winetest_trace( const char *msg, ... ) WINETEST_PRI
 #include <stdio.h>
 #include <excpt.h>
 
-#if defined(__x86_64__) && defined(__GNUC__) && defined(__WINE_USE_MSVCRT)
+#if (defined(__x86_64__) || defined(__aarch64__)) && defined(__GNUC__) && defined(__WINE_USE_MSVCRT)
 # define __winetest_va_start(list,arg) __builtin_ms_va_start(list,arg)
 # define __winetest_va_end(list) __builtin_ms_va_end(list)
 #else