diff --git a/CMakeLists.txt b/CMakeLists.txt
index c532f6a7e..c741c7f96 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,6 +43,7 @@ include(CheckCmakeCompat)
 # Include cmake modules
 include(CheckIncludeFiles)
 include(CheckLibraryExists)
+include(CheckSymbolExists)
 include(CheckStructHasMember)
 include(FindPkgConfig)
 include(TestBigEndian)
@@ -131,7 +132,8 @@ endif()
 # Compiler-specific flags
 if(CMAKE_COMPILER_IS_GNUCC)
 	if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64" OR CMAKE_SYSTEM_PROCESSOR MATCHES "i686")
-		if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+		CHECK_SYMBOL_EXISTS(__x86_64__ "" IS_X86_64)
+		if(IS_X86_64)
 			set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
 		else()
 			set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=i686")