Linux link time optimisation

[jd-13]

Attempted to enable in commit 54f60f3, causes clang build error:

Linking MONSTR - Shared Code
Linking MONSTR - VST3
/usr/bin/ld: build/MONSTR.a: error adding symbols: archive has no index; run ranlib to add one
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:146: build/MONSTR.vst3/Contents/x86_64-linux/MONSTR.so] Error 1
Error: Process completed with exit code 2.