Remove X86 setting from README.md (#998)

README.md

@@ -63,12 +63,13 @@ Building and Running Translation Validation
 
 Alive2's `opt` and `clang` translation validation requires a build of LLVM with
 RTTI and exceptions turned on.
-LLVM can be built targeting X86 in the following way.  (You may prefer to add `-DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++` to the CMake step if your default compiler is `gcc`.)
+LLVM can be built in the following way.
+(You may prefer to add `-DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_ENABLE_LLD=ON` to the CMake step if your default compiler is `gcc`.)
 ```
 cd $LLVM2_HOME
 mkdir build
 cd build
-cmake -GNinja -DLLVM_ENABLE_RTTI=ON -DLLVM_ENABLE_EH=ON -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="llvm;clang" ../llvm
+cmake -GNinja -DLLVM_ENABLE_RTTI=ON -DLLVM_ENABLE_EH=ON -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="llvm;clang" ../llvm
 ninja
 ```