How to reproduce

Using MSVC and compiling a source file with any /Zc:<flag> parameter (C++ conformance modes), e.g. /Zc:throwingNew

Actual behavior

ccache complains about this compiler option:
Compiler option /Zc:throwingNew is unsupported

Expected behavior

In version 4.7.4 the conformance options worked just fine.

Environment

ccache version 4.8

I figured out that this issue goes away when I revert d099c18.

A brief look into the patch revealed that the simple check for -Z wrongly matches the conformance flags as well.