Remove stray word

configure

@@ -594,7 +594,7 @@ opt docs     1 "build standard library documentation"
 opt compiler-docs     0 "build compiler documentation"
 opt optimize-tests 1 "build tests with optimizations"
 opt debuginfo-tests 0 "build tests with debugger metadata"
-opt libcpp 1 "build with llvm with libc++ instead of libstdc++ when using clang"
+opt libcpp 1 "build llvm with libc++ instead of libstdc++ when using clang"
 opt llvm-assertions 0 "build LLVM with assertions"
 opt debug-assertions 0 "build with debugging assertions"
 opt fast-make 0 "use .gitmodules as timestamp for submodule deps"