diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b55a5a..4e4f9bb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.2)
+cmake_minimum_required (VERSION 2.8)
 include(CheckFunctionExists)
 include(CheckIncludeFiles)
 
@@ -10,6 +10,13 @@ if(CMAKE_SYSTEM_NAME MATCHES "OpenBSD")
 	add_definitions(-DHAVE_ATTRIBUTE__BOUNDED__)
 endif()
 
+if(CMAKE_SYSTEM_NAME MATCHES "Linux")
+	add_definitions(-D_DEFAULT_SOURCE)
+	add_definitions(-D_BSD_SOURCE)
+	add_definitions(-D_POSIX_SOURCE)
+	add_definitions(-D_GNU_SOURCE)
+endif()
+
 add_definitions(-DLIBRESSL_INTERNAL)
 add_definitions(-DOPENSSL_NO_HW_PADLOCK)
 add_definitions(-DOPENSSL_NO_ASM)
diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
index 2a1e86c..3a866eb 100644
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -617,6 +617,8 @@ if(NOT HAVE_ARC4RANDOM_BUF)
 			set(CRYPTO_SRC ${CRYPTO_SRC} compat/getentropy_aix.c)
 		elseif(CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
 			set(CRYPTO_SRC ${CRYPTO_SRC} compat/getentropy_freebsd.c)
+		elseif(CMAKE_SYSTEM_NAME MATCHES "Linux")
+			set(CRYPTO_SRC ${CRYPTO_SRC} compat/getentropy_linux.c)
 		elseif(CMAKE_SYSTEM_NAME MATCHES "NetBSD")
 			set(CRYPTO_SRC ${CRYPTO_SRC} compat/getentropy_netbsd.c)
 		elseif(CMAKE_SYSTEM_NAME MATCHES "Darwin")