[NFC][UR] Don't check for __cplusplus in cpp files (#19112)

Unless something has gone terribly wrong, the compiler used to compile
cpp files will be a cpp compiler.

Author: RossBrunton

unified-runtime/scripts/templates/ldrddi.cpp.mako

@@ -90,9 +90,7 @@ namespace ur_loader
     %endfor
 } // namespace ur_loader
 
-#if defined(__cplusplus)
 extern "C" {
-#endif
 
 %for tbl in th.get_pfntables(specs, meta, n, tags):
 %if 'guard' in tbl:
@@ -176,6 +174,4 @@ ${tbl['export']['name']}(
 
 %endfor
 
-#if defined(__cplusplus)
 }
-#endif

unified-runtime/scripts/templates/mockddi.cpp.mako

@@ -162,9 +162,7 @@ namespace driver
     %endfor
 } // namespace driver
 
-#if defined(__cplusplus)
 extern "C" {
-#endif
 
 %for tbl in th.get_pfntables(specs, meta, n, tags):
 %if 'guard' in tbl:
@@ -218,6 +216,4 @@ try {
 %endif
 
 %endfor
-#if defined(__cplusplus)
 }
-#endif

unified-runtime/scripts/templates/ur_interface_loader.cpp.mako

@@ -38,7 +38,7 @@ static ur_result_t validateProcInputs(ur_api_version_t version, void *pDdiTable)
 
 #ifdef UR_STATIC_ADAPTER_${Adapter}
 namespace ${n}::${adapter} {
-#elif defined(__cplusplus)
+#else
 extern "C" {
 #endif
 
@@ -77,7 +77,7 @@ ${X}_APIEXPORT ${x}_result_t ${X}_APICALL ${tbl['export']['name']}(
 
 #ifdef UR_STATIC_ADAPTER_${Adapter}
 } // namespace ur::${adapter}
-#elif defined(__cplusplus)
+#else
 } // extern "C"
 #endif
 

unified-runtime/source/adapters/cuda/ur_interface_loader.cpp

@@ -29,9 +29,7 @@ ur_result_t validateProcInputs(ur_api_version_t version, void *pDdiTable) {
 }
 } // namespace
 
-#if defined(__cplusplus)
 extern "C" {
-#endif
 
 UR_DLLEXPORT ur_result_t UR_APICALL urGetPlatformProcAddrTable(
     ur_api_version_t version, ur_platform_dditable_t *pDdiTable) {
@@ -487,9 +485,7 @@ UR_DLLEXPORT ur_result_t UR_APICALL urAllAddrTable(ur_api_version_t version,
   return UR_RESULT_SUCCESS;
 }
 
-#if defined(__cplusplus)
 } // extern "C"
-#endif
 
 const ur_dditable_t *ur::cuda::ddi_getter::value() {
   static std::once_flag flag;

unified-runtime/source/adapters/hip/ur_interface_loader.cpp

@@ -29,9 +29,7 @@ ur_result_t validateProcInputs(ur_api_version_t version, void *pDdiTable) {
 }
 } // namespace
 
-#if defined(__cplusplus)
 extern "C" {
-#endif
 
 UR_DLLEXPORT ur_result_t UR_APICALL urGetPlatformProcAddrTable(
     ur_api_version_t version, ur_platform_dditable_t *pDdiTable) {
@@ -480,9 +478,7 @@ UR_DLLEXPORT ur_result_t UR_APICALL urAllAddrTable(ur_api_version_t version,
   return UR_RESULT_SUCCESS;
 }
 
-#if defined(__cplusplus)
 } // extern "C"
-#endif
 
 const ur_dditable_t *ur::hip::ddi_getter::value() {
   static std::once_flag flag;

unified-runtime/source/adapters/level_zero/ur_interface_loader.cpp

@@ -29,9 +29,7 @@ ur_result_t validateProcInputs(ur_api_version_t Version, void *pDdiTable) {
 }
 } // namespace
 
-#if defined(__cplusplus)
 extern "C" {
-#endif
 
 UR_DLLEXPORT ur_result_t UR_APICALL urGetAdapterProcAddrTable(
     ur_api_version_t version, ur_adapter_dditable_t *pDdiTable) {
@@ -467,9 +465,7 @@ UR_DLLEXPORT ur_result_t UR_APICALL urAllAddrTable(ur_api_version_t version,
   return UR_RESULT_SUCCESS;
 }
 
-#if defined(__cplusplus)
 } // extern "C"
-#endif
 
 const ur_dditable_t *ur::opencl::ddi_getter::value() {
   static std::once_flag flag;