Fix compilation issues under clang

clang defaults to c99 so remove inline statements( http://clang.llvm.org/compatibility.html#inline ) on functions sharedacross different translation units.
clang's linker doesn't like major numbers over 255 ( https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/ld.1.html -current_version) so change how SOREL is generated in Makefile.am.