cmake : bump to 3.12 (#768)

This CMakeLists.txt file uses Cmake command `add_compile_definitions()`.

That command did not exist until CMake 3.12.

Reference documentation:
https://cmake.org/cmake/help/latest/command/add_compile_definitions.html

I see a failure in CMake 3.10 with existing CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2249363d969924f21020493932476f032db0045c..1a599dd358fc8b4da213c72a7842695fc8640d11 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.3)
+cmake_minimum_required (VERSION 3.12)
 project(ggml VERSION 0.1.0)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS "on")