GCC / G++ path include flags starts with '='

Question

I tried to write platform-independent build file (for ninja) and try to avoid specifying the full paths such as D:/tools/x64/msys2/ucrt64/include/librsvg-2.0 or /usr/include/librsvg-2.0 .

GCC docs say that

If dir begins with '=' or $SYSROOT, then the '=' or $SYSROOT is replaced by the sysroot prefix; see --sysroot and -isysroot.

But on Windows with MSYS2 environment when I set flags like -I=librsvg-2.0 or -I=/librsvg-2.0 it has no effect. Can it be MSYS2 only behaviour, or I do something wrong?

Answer 1

Well, GCC has own system include paths, but it doesn't have the default $SYSROOT value. So first you need to set it using the --sysroot=your_path flag, if you want use -I= .