File extern_c_for_cpp.patch of Package soundtouch

diff --git a/source/SoundTouchDLL/SoundTouchDLL.h b/source/SoundTouchDLL/SoundTouchDLL.h
index 1dde9b0..98a1f32 100644
--- a/source/SoundTouchDLL/SoundTouchDLL.h
+++ b/source/SoundTouchDLL/SoundTouchDLL.h
@@ -33,16 +33,19 @@
 #ifndef _SoundTouchDLL_h_
 #define _SoundTouchDLL_h_
 
+#ifdef __cplusplus
+    #define EXTERN_C extern "C"
+#else
+    #define EXTERN_C
+#endif
+
 #if defined(_WIN32) || defined(WIN32)
     // Windows
-    #ifndef __cplusplus
-        #error "Expected g++"
-    #endif
 
     #ifdef DLL_EXPORTS
-        #define SOUNDTOUCHDLL_API extern "C" __declspec(dllexport)
+        #define SOUNDTOUCHDLL_API EXTERN_C __declspec(dllexport)
     #else
-        #define SOUNDTOUCHDLL_API extern "C" __declspec(dllimport)
+        #define SOUNDTOUCHDLL_API EXTERN_C __declspec(dllimport)
     #endif
 
 #else
@@ -50,10 +53,10 @@
 
     #if defined(DLL_EXPORTS) || defined(SoundTouchDLL_EXPORTS)
         // GCC declaration for exporting functions
-        #define SOUNDTOUCHDLL_API extern "C" __attribute__((__visibility__("default")))
+        #define SOUNDTOUCHDLL_API EXTERN_C __attribute__((__visibility__("default")))
     #else
         // import function
-        #define SOUNDTOUCHDLL_API extern "C"
+        #define SOUNDTOUCHDLL_API EXTERN_C
     #endif
 
     // Linux-replacements for Windows declarations: