ObjectMetadataBuilder builds serialized module metadata include in
an object. In addition, it also relies on information from ModuleInfo
to build a table of function pointers, trmampolines and dynamic function
trampoline pointers. ObjectMetadataBuilder takes care of setting up
relocations, so a linker can automatically fill in actual addresses of
all relevant functions. There is no need to piece the information together
in the glue C file.