diff --git a/core/foundation/inc/TError.h b/core/foundation/inc/TError.h
index 0099d8e538704..2948a70e6844e 100644
--- a/core/foundation/inc/TError.h
+++ b/core/foundation/inc/TError.h
@@ -39,15 +39,14 @@
 
 class TVirtualMutex;
 
-constexpr Int_t kUnset    =  -1;
-constexpr Int_t kPrint    =   0;
-constexpr Int_t kInfo     =   1000;
-constexpr Int_t kWarning  =   2000;
-constexpr Int_t kError    =   3000;
-constexpr Int_t kBreak    =   4000;
-constexpr Int_t kSysError =   5000;
-constexpr Int_t kFatal    =   6000;
-
+R__EXTERN const Int_t kUnset;
+R__EXTERN const Int_t kPrint;
+R__EXTERN const Int_t kInfo;
+R__EXTERN const Int_t kWarning;
+R__EXTERN const Int_t kError;
+R__EXTERN const Int_t kBreak;
+R__EXTERN const Int_t kSysError;
+R__EXTERN const Int_t kFatal;
 
 // TROOT sets the error ignore level handler, the system error message handler, and the error abort handler on
 // construction such that the "Root.ErrorIgnoreLevel" environment variable is used for the ignore level
diff --git a/core/foundation/src/RLogger.cxx b/core/foundation/src/RLogger.cxx
index de9eb939ab8ec..18ba9f954d959 100644
--- a/core/foundation/src/RLogger.cxx
+++ b/core/foundation/src/RLogger.cxx
@@ -52,7 +52,7 @@ inline bool RLogHandlerDefault::Emit(const RLogEntry &entry)
    if (!entry.fLocation.fFuncName.empty())
       strm << " in " << entry.fLocation.fFuncName;
 
-   static constexpr const int errorLevelOld[] = {kFatal /*unset*/, kFatal, kError, kWarning, kInfo, kInfo /*debug*/};
+   static const int errorLevelOld[] = {kFatal /*unset*/, kFatal, kError, kWarning, kInfo, kInfo /*debug*/};
    (*::GetErrorHandler())(errorLevelOld[cappedLevel], entry.fLevel == ELogLevel::kFatal, strm.str().c_str(),
                           entry.fMessage.c_str());
    return true;
diff --git a/core/foundation/src/TError.cxx b/core/foundation/src/TError.cxx
index 8f27b76c5d72b..969f11f48a33a 100644
--- a/core/foundation/src/TError.cxx
+++ b/core/foundation/src/TError.cxx
@@ -28,6 +28,15 @@ to be replaced by the proper DefaultErrorHandler()
 #include <cerrno>
 #include <string>
 
+const Int_t kUnset = -1;
+const Int_t kPrint = 0;
+const Int_t kInfo = 1000;
+const Int_t kWarning = 2000;
+const Int_t kError = 3000;
+const Int_t kBreak = 4000;
+const Int_t kSysError = 5000;
+const Int_t kFatal = 6000;
+
 Int_t  gErrorIgnoreLevel     = kUnset;
 Int_t  gErrorAbortLevel      = kSysError+1;
 Bool_t gPrintViaErrorHandler = kFALSE;