linker/compiler errors are silently consumed and don't appear in stdout or stderr

[compnerd]

Description

Some recent work that @neonichu (or @tomerd?) did to silence some output seems to have resulted in linker errors being silently dropped making it difficult to identify build failures.

Expected behavior

Linker errors should be presented to the user.

Actual behavior

No response

Steps to reproduce

swift build a project that has undefined references.

Swift Package Manager version/commit hash

No response

Swift & OS version (output of swift --version ; uname -a)

Windows 11

[al45tair]

It also seems to have silenced some compiler errors too.

...
/home/alastair/Source/grpc-swift/.build/checkouts/swift-nio/Sources/CNIOLinux/shim.c:112:25: error: unknown type name 'cpu_set_t'
void CNIOLinux_CPU_ZERO(cpu_set_t *set) {
                        ^
/home/alastair/Source/grpc-swift/.build/checkouts/swift-nio/Sources/CNIOLinux/shim.c:113:5: error: call to undeclared function 'CPU_ZERO'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    CPU_ZERO(set);
    ^
/home/alastair/Source/grpc-swift/.build/checkouts/swift-nio/Sources/CNIOLinux/shim.c:116:34: error: unknown type name 'cpu_set_t'
int CNIOLinux_CPU_ISSET(int cpu, cpu_set_t *set) {
                                 ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

only now appears if I pass -v.

[compnerd]

@al45tair I just happened to run into that same thing on Windows!

[neonichu]

Seems like we should revert #7078 -- we'll need a broader change to address the issue with code-signing output.