BUG: cmake_minimum_required must be the first command

https://cmake.org/cmake/help/v3.5/command/project.html

Note: Call the cmake_minimum_required() command at the beginning of the
top-level CMakeLists.txt file even before calling the project() command.
It is important to establish version and policy settings before invoking
other commands whose behavior they may affect. See also policy CMP0000.

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef78e3f..f083dc3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,8 @@
-project(Eigen3)
-
+# cmake_minimum_require must be the first command of the file
 cmake_minimum_required(VERSION 3.5.0)
 
+project(Eigen3)
+
 # guard against in-source builds
 
 if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
@@ -667,4 +668,4 @@
 
 if (EIGEN_SPLIT_TESTSUITE)
   ei_split_testsuite("${EIGEN_SPLIT_TESTSUITE}")
-endif()
\ No newline at end of file
+endif()