build BUGFIX do not use cmake_minimum_required() multiple times
Remove use of this macro from all libyang's cmake modules to avoid
possible isseus with cmake policies (cmake_policy())
diff --git a/CMakeModules/ABICheck.cmake b/CMakeModules/ABICheck.cmake
index 472c880..f9204ab 100644
--- a/CMakeModules/ABICheck.cmake
+++ b/CMakeModules/ABICheck.cmake
@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 2.8.12)
-
# generate API/ABI report
macro(LIBYANG_ABICHECK)
find_program(ABI_DUMPER abi-dumper)
diff --git a/CMakeModules/Doc.cmake b/CMakeModules/Doc.cmake
index 9301d43..f10b864 100644
--- a/CMakeModules/Doc.cmake
+++ b/CMakeModules/Doc.cmake
@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 2.8.12)
-
# Prepare building doxygen documentation
macro(LIBYANG_DOC)
find_package(Doxygen)
diff --git a/CMakeModules/SourceFormat.cmake b/CMakeModules/SourceFormat.cmake
index 7a01f29..d3655ad 100644
--- a/CMakeModules/SourceFormat.cmake
+++ b/CMakeModules/SourceFormat.cmake
@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 2.8.12)
-
# format source files with uncrustify
# files are expected to be a list and relative paths are resolved wtih respect to CMAKE_SOURCE DIR
macro(SOURCE_FORMAT)
diff --git a/CMakeModules/UseCompat.cmake b/CMakeModules/UseCompat.cmake
index 1e92bb7..13e77c6 100644
--- a/CMakeModules/UseCompat.cmake
+++ b/CMakeModules/UseCompat.cmake
@@ -1,5 +1,3 @@
-cmake_minimum_required(VERSION 2.8.12)
-
include(CheckSymbolExists)
include(TestBigEndian)