[cmake] Back out of making unsupported -no_exported_symbols linker a

fatal error for now

Appeases build bots while being investigated.

Author: cyndyishida

llvm/cmake/modules/AddLLVM.cmake

@@ -1038,14 +1038,9 @@ macro(add_llvm_executable name)
     add_llvm_symbol_exports( ${name} ${LLVM_EXPORTED_SYMBOL_FILE} )
   endif(LLVM_EXPORTED_SYMBOL_FILE)
 
-  if (NOT LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES) 
-    if(LLVM_LINKER_SUPPORTS_NO_EXPORTED_SYMBOLS)
+  if (NOT LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES AND LLVM_LINKER_SUPPORTS_NO_EXPORTED_SYMBOLS)
       set_property(TARGET ${name} APPEND_STRING PROPERTY
         LINK_FLAGS " -Wl,-no_exported_symbols")
-    else()
-      message(FATAL_ERROR 
-        "LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES cannot be disabled when linker does not support \"-no_exported_symbols\"")
-    endif()
   endif()
 
   if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)