diff --git a/sdk/lib/crt/math/math.cmake b/sdk/lib/crt/math/math.cmake
index b54c21b0a42..a888242644e 100644
--- a/sdk/lib/crt/math/math.cmake
+++ b/sdk/lib/crt/math/math.cmake
@@ -6,6 +6,7 @@ list(APPEND LIBCNTPR_MATH_SOURCE
     math/abs.c
     math/div.c
     math/labs.c
+    math/sincos.c
 )
 
 if(ARCH STREQUAL "i386")
diff --git a/sdk/lib/crt/math/sincos.c b/sdk/lib/crt/math/sincos.c
new file mode 100644
index 00000000000..6c22e452906
--- /dev/null
+++ b/sdk/lib/crt/math/sincos.c
@@ -0,0 +1,15 @@
+/*
+ * PROJECT:     ReactOS CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Fallback implementation of sincos
+ * COPYRIGHT:   Copyright 2022 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <math.h>
+
+// This is a very simplistic implementation to make GCC 11 happy
+void sincos(double x, double *s, double *c)
+{
+    *s = sin(x);
+    *c = cos(x);
+}
diff --git a/sdk/lib/crt/msvcrtex.cmake b/sdk/lib/crt/msvcrtex.cmake
index 272d844252e..d7a513012b4 100644
--- a/sdk/lib/crt/msvcrtex.cmake
+++ b/sdk/lib/crt/msvcrtex.cmake
@@ -3,6 +3,7 @@ include_directories(include/internal/mingw-w64)
 
 list(APPEND MSVCRTEX_SOURCE
     ${CRT_STARTUP_SOURCE}
+    math/sincos.c
     misc/dbgrpt.cpp
     misc/fltused.c
     misc/isblank.c