diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ecb944c7b..758e7fefa8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,7 +67,11 @@ message(STATUS "curl version=[${CURL_VERSION}]")
 # SET(PACKAGE_STRING "curl-")
 # SET(PACKAGE_BUGREPORT "a suitable curl mailing list => https://curl.se/mail/")
 set(OPERATING_SYSTEM "${CMAKE_SYSTEM_NAME}")
-set(OS "\"${CMAKE_SYSTEM_NAME}${CURL_OS_SUFFIX}\"")
+if(CMAKE_C_COMPILER_TARGET)
+  set(OS "\"${CMAKE_C_COMPILER_TARGET}\"")
+else()
+  set(OS "\"${CMAKE_SYSTEM_NAME}\"")
+endif()
 
 include_directories(${CURL_SOURCE_DIR}/include)
 
diff --git a/lib/config-win32.h b/lib/config-win32.h
index 932515667f..25e81cf190 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -663,7 +663,7 @@ Vista
 /* ---------------------------------------------------------------- */
 
 /* Define cpu-machine-OS */
-#undef OS
+#if !defined(OS)
 #if defined(_M_IX86) || defined(__i386__) /* x86 (MSVC or gcc) */
 #define OS "i386-pc-win32"
 #elif defined(_M_X64) || defined(__x86_64__) /* x86_64 (MSVC >=2005 or gcc) */
@@ -677,6 +677,7 @@ Vista
 #else
 #define OS "unknown-pc-win32"
 #endif
+#endif
 
 /* Name of package */
 #define PACKAGE "curl"