Bump minimum CMake version.

CMake 3.10 was released November 20, 2017, which is now more than five
years ago.

Change-Id: Ic939fd137983914ce1041740f58d98a56433e739
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/55271
Commit-Queue: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
diff --git a/BUILDING.md b/BUILDING.md
index 73bc29c..b1ccf45 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -10,7 +10,7 @@
 [Abseil guidelines](https://abseil.io/about/compatibility). If in doubt, use the
 most recent stable version of each tool.
 
-  * [CMake](https://cmake.org/download/) 3.8 or later is required.
+  * [CMake](https://cmake.org/download/) 3.10 or later is required.
 
   * A recent version of Perl is required. On Windows,
     [Active State Perl](http://www.activestate.com/activeperl/) has been
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 780ed21..ce55363 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.8)
+cmake_minimum_required(VERSION 3.10)
 
 # Defer enabling C and CXX languages.
 project(BoringSSL NONE)