[cmake] Prevent implicitly passing -no_exported_symbols (#87846)

* It is possible to setup llvm-project builds without going through
`llvm/CMakeList.txt` so the fatal error handling should be smarter.
* Disable option on Apple style lldb-linux builds.

Author: cyndyishida

lldb/cmake/caches/Apple-lldb-Linux.cmake

@@ -1,4 +1,5 @@
 include(${CMAKE_CURRENT_LIST_DIR}/Apple-lldb-base.cmake)
+set(LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES ON CACHE BOOL "")
 
 set(LLVM_DISTRIBUTION_COMPONENTS
   lldb

llvm/cmake/modules/AddLLVM.cmake

@@ -1038,9 +1038,15 @@ 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 AND LLVM_LINKER_SUPPORTS_NO_EXPORTED_SYMBOLS)
+  if (DEFINED LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES AND 
+      NOT LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES)
+    if(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)