Bump minimum CMake version.

CMake 3.5.0 was released March 8, 2016. Per our five year rule, we
can require that now:
https://cmake.org/pipermail/cmake/2016-March/062947.html

Change-Id: I916fdb66e0356e3a8ffbe1e5fa89f51d99a78546
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46345
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/BUILDING.md b/BUILDING.md
index 2d156ec..f76c571 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/) 3.0 or later is required.
+  * [CMake](https://cmake.org/download/) 3.5 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 f58e853..ef162fd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.3)
+cmake_minimum_required(VERSION 3.5)
 
 # Defer enabling C and CXX languages.
 project(BoringSSL NONE)
diff --git a/util/generate_build_files.py b/util/generate_build_files.py
index 9d71498..7341a2f 100644
--- a/util/generate_build_files.py
+++ b/util/generate_build_files.py
@@ -428,7 +428,7 @@
 
 # This file is created by generate_build_files.py. Do not edit manually.
 
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.5)
 
 project(BoringSSL LANGUAGES C CXX)