Compile dependencies statically into the binary.

On Linux when building this under RPM, RPM insisted on linking in
standard system libraries like libpng, libjpeg-turbo, libGLEW,
Lua, etc. This patch causes all dependencies to be statically
compiled into the binary, which is ideal as the alternative is
segfaulting because of incompatible library changes.

StepMania also uses a modified Lua library which exports functions
that don't exist in any standard Lua library, so there's no easy
way around this.

extern/CMakeProject-lua.cmake

@@ -58,7 +58,7 @@ set(LUA_HPP
 source_group("" FILES ${LUA_SRC})
 source_group("" FILES ${LUA_HPP})
 
-add_library("lua-5.1" ${LUA_SRC} ${LUA_HPP})
+add_library("lua-5.1" STATIC ${LUA_SRC} ${LUA_HPP})
 
 set_property(TARGET "lua-5.1" PROPERTY FOLDER "External Libraries")