Revert "Revert "Revert "Cleanup some numeric code."""

core/src/fxcrt/fx_extension.cpp

Index: core/src/fxcrt/fx_extension.cpp
diff --git a/core/src/fxcrt/fx_extension.cpp b/core/src/fxcrt/fx_extension.cpp
index 4951fbde9c9e4bacbe7ea972f7e0948729a04a78..d64a06d08b7fcc2dfc6f070037e73f76bb1aa7b4 100644
--- a/core/src/fxcrt/fx_extension.cpp
+++ b/core/src/fxcrt/fx_extension.cpp
@@ -7,7 +7,6 @@
 #include "../../include/fxcrt/fx_basic.h"
 #include "../../include/fxcrt/fx_ext.h"
 #include "extension.h"
-
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
 #include <wincrypt.h>
 #else
@@ -51,7 +50,9 @@ IFX_MemoryStream* FX_CreateMemoryStream(uint8_t* pBuffer,
 IFX_MemoryStream* FX_CreateMemoryStream(FX_BOOL bConsecutive) {
   return new CFX_MemoryStream(bConsecutive);
 }
-
+#ifdef __cplusplus
+extern "C" {
+#endif
 FX_FLOAT FXSYS_tan(FX_FLOAT a) {
   return (FX_FLOAT)tan(a);
 }
@@ -188,7 +189,12 @@ FX_DWORD FX_HashCode_String_GetW(const FX_WCHAR* pStr,
   }
   return dwHashCode;
 }
-
+#ifdef __cplusplus
+}
+#endif
+#ifdef __cplusplus
+extern "C" {
+#endif
 void* FX_Random_MT_Start(FX_DWORD dwSeed) {
   FX_LPMTRANDOMCONTEXT pContext = FX_Alloc(FX_MTRANDOMCONTEXT, 1);
   pContext->mt[0] = dwSeed;
@@ -291,4 +297,6 @@ void FX_Random_GenerateCrypto(FX_DWORD* pBuffer, int32_t iCount) {
   FX_Random_GenerateBase(pBuffer, iCount);
 #endif
 }
-
+#ifdef __cplusplus
+}
+#endif