I'm not sure about C, but it's definitely the case that Go compiles magnitudes faster than C++, for any reasonable sized project. For example, the ~200k lines of Go standard library compiles in about 14 seconds on my workstation, while random C++ libraries frequently take much longer (just my anecdotal impression from waiting on "brew install").
Also the language is quite complex and requires multiple analyses at parse time to decide what the developer is really trying to do.
C code can be compiled fast if not many optimizations are being made. For example the Tiny C compiler was compiling the Linux kernel around 15s in 2004, not sure about which modules were configured though.
Any proper compiler for a language with modules should anyway be able to beat C and C++ compilers hands down.