diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a41cf4f7..239b80ae 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,6 @@
 .ubuntu: &ubuntu_def
   variables:
-    CMAKE_VERSION: 3.12.1
+    CMAKE_VERSION: 3.9.6
   before_script:
     - REPOSITORY="$PWD" && cd ..
     - apt-get update && apt-get install -y dpkg-dev wget g++ gcc libncurses5-dev libreadline-dev libssl-dev make zlib1g-dev git file
@@ -23,11 +23,7 @@ trusty:
   <<: *ubuntu_def
   image: ubuntu:trusty
 
-#
-# there's no cmake3 for 12.04
-# maybe, there's ppa ?
-#
-#precise:
-#  <<: *ubuntu_def
-#  image: ubuntu:precise
+precise:
+  <<: *ubuntu_def
+  image: ubuntu:precise
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index eaa53315..e04ed733 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,6 +26,9 @@ if (NOT ${PROJECT_VERSION} VERSION_EQUAL "${CurrentBuild_MAJOR}.${CurrentBuild_M
   message (FATAL_ERROR "PROJECT_VERSION does not match to src/CurrentBuild.txt")
 endif()
 
+include(CheckIncludeFile)
+Check_Include_File(sys/auxv.h HAVE_SYS_AUXV)
+
 configure_file("${SoftEtherVPN_SOURCE_DIR}/AUTHORS.TXT" "${SoftEtherVPN_SOURCE_DIR}/src/bin/hamcore/authors.txt" COPYONLY)
 
 set(BUILD_DIRECTORY ${SoftEtherVPN_SOURCE_DIR}/build)
diff --git a/src/Mayaqua/CMakeLists.txt b/src/Mayaqua/CMakeLists.txt
index 1117f637..81ece532 100644
--- a/src/Mayaqua/CMakeLists.txt
+++ b/src/Mayaqua/CMakeLists.txt
@@ -19,11 +19,24 @@ find_package(ZLIB REQUIRED)
 # In some cases libiconv is not included in libc
 find_library(LIB_ICONV iconv)
 
-add_subdirectory(cpu_features)
+if(HAVE_SYS_AUXV)
+  add_subdirectory(cpu_features)
+endif()
 
 target_include_directories(mayaqua PRIVATE cpu_features/include)
 
-target_link_libraries(mayaqua cpu_features OpenSSL::SSL OpenSSL::Crypto Threads::Threads ZLIB::ZLIB)
+target_link_libraries(mayaqua OpenSSL::SSL OpenSSL::Crypto Threads::Threads ZLIB::ZLIB)
+
+if(HAVE_SYS_AUXV)
+  target_link_libraries(mayaqua cpu_features)
+else()
+  add_definitions(-DSKIP_CPU_FEATURES)
+endif()
+
+find_library(LIB_RT rt)
+if(LIB_RT)
+  target_link_libraries(mayaqua rt)
+endif()
 
 if(LIB_ICONV)
   target_link_libraries(mayaqua ${LIB_ICONV})
diff --git a/src/Mayaqua/Encrypt.c b/src/Mayaqua/Encrypt.c
index ca157a22..1c24cbbd 100644
--- a/src/Mayaqua/Encrypt.c
+++ b/src/Mayaqua/Encrypt.c
@@ -148,7 +148,11 @@
 #ifdef _MSC_VER
 	#include <intrin.h> // For __cpuid()
 #else // _MSC_VER
+
+#ifndef SKIP_CPU_FEATURES
 	#include "cpu_features_macros.h"
+#endif
+
 	#if defined(CPU_FEATURES_ARCH_X86)
 		#include "cpuinfo_x86.h"
 	#elif defined(CPU_FEATURES_ARCH_ARM)