Allow forcing 32 bit builds on 64 bit platforms

Author: mattsta

CMakeLists.txt

@@ -28,9 +28,17 @@ else()
     set(_lua_module_dir "${_lua_lib_dir}/lua/5.1")
 endif()
 
+option(Build32Bit "Build 32-bit Library" OFF)
+
 set(CMAKE_C_FLAGS "-O2 -g -ggdb -Wall -pedantic -std=c99")
 add_library(cmsgpack MODULE lua_cmsgpack.c)
 set_target_properties(cmsgpack PROPERTIES PREFIX "")
+
+if(Build32Bit)
+    set_target_properties(cmsgpack
+                          PROPERTIES COMPILE_FLAGS "-m32" LINK_FLAGS "-m32")
+endif()
+
 target_link_libraries(cmsgpack ${_MODULE_LINK})
 install(TARGETS cmsgpack DESTINATION "${_lua_module_dir}")
 

README.md

@@ -83,6 +83,13 @@ Build and test:
     make
     lua ../test.lua
 
+You can build a 32-bit module on a 64-bit platform with:
+
+    mkdir build; cd build
+    cmake -DBuild32Bit=ON ..
+    make
+    lua ../test.lua
+
 NESTED TABLES
 ---
 Nested tables are handled correctly up to `LUACMSGPACK_MAX_NESTING` levels of