[NFC][libc++] Fix typo in the description of LIBCXX_INCLUDE_BENCHMARKS

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342822 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f4c7c93..3eea1bd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,7 +77,7 @@
 option(LIBCXX_INCLUDE_TESTS "Build the libc++ tests." ${LLVM_INCLUDE_TESTS})
 
 # Benchmark options -----------------------------------------------------------
-option(LIBCXX_INCLUDE_BENCHMARKS "Build the libc++ benchmarks and their dependancies" ON)
+option(LIBCXX_INCLUDE_BENCHMARKS "Build the libc++ benchmarks and their dependencies" ON)
 set(LIBCXX_BENCHMARK_NATIVE_STDLIB "" CACHE STRING
         "Build the benchmarks against the specified native STL.
          The value must be one of libc++/libstdc++")