Cannot find stdio.h

Question

I am using macOS.

I am trying to build the code of mozilla-central.

While running the command ./mach build, the build fails at the compile step. Here are the relevant stack traces:

stack backtrace:  0:20.24    0:        0x10436b5ff - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::hed04c7a1477ef1e3  0:20.24    1:        0x10434499d - std::sys_common::backtrace::print::h336400f22676933f  0:20.24    2:        0x104373bd3 - std::panicking::default_hook::{{closure}}::h0d6700a02d682978  0:20.24    3:        0x10437395c - std::panicking::default_hook::h90363c6d6ac04260  0:20.24    4:        0x1043742fb - std::panicking::rust_panic_with_hook::h81c4f3add25e6667  0:20.24    5:        0x1043740ce - std::panicking::continue_panic_fmt::hfa057b7c1de88179  0:20.24    6:        0x104374020 - std::panicking::begin_panic_fmt::hd1123702300ea9f2  0:20.24    7:        0x1035f4e6d - build_script_build::build_gecko::bindings::write_binding_file::h2d9a397b93e6a614  0:20.24    8:        0x1035f651c - build_script_build::build_gecko::bindings::generate_bindings::ha066bc11b076e01d  0:20.24    9:        0x1043808fe - __rust_maybe_catch_panic  0:20.24   10:        0x1035eea9f - std::panicking::try::hcbd901ede6e8004c  0:20.32   11:        0x1035e335c - <F as alloc::boxed::FnBox<A>>::call_box::h638a7c5eb8c94414  0:20.33   12:        0x104373037 - std::sys_common::thread::start_thread::h78b1dd404be976ad  0:20.33   13:        0x1043436c8 - std::sys::unix::thread::Thread::new::thread_start::h27c6becca8cf44e0  0:20.33   14:     0x7fff636208cc - _pthread_body  0:20.33   15:     0x7fff6362083e - _pthread_start  0:20.33 /usr/local/Cellar/llvm/6.0.1/include/c++/v1/stdio.h:108:15: fatal error: 'stdio.h' file not found  0:20.33 /usr/local/Cellar/llvm/6.0.1/include/c++/v1/stdio.h:108:15: fatal error: 'stdio.h' file not found, err: true  0:20.37 thread '<unnamed>' panicked at 'Failed to generate bindings 

According to me, the root cause is:

/usr/local/Cellar/llvm/6.0.1/include/c++/v1/stdio.h:108:15: fatal error: 'stdio.h' file not found, err: true 

The solution listed online was to install xcode command line tools using:

xcode-select --install 

I have already done this.

Answer 1

The root reason is due to a missing /usr/include directory.

Installing command-line tools (xcode-select --install), sometimes, will not automatically add it.

The Link shows the correct way: After installing command-line tools Install the package at:

# run this in Terminal open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg 

After that,

you should have a directory /usr/include with header files

Answer 2

Try setting SDKROOT explicitly to the system SDK:

export SDKROOT=$(xcrun --sdk macosx --show-sdk-path) 

Doing it avoids the need for creating symlinks in /usr.

This error seem recurrent, for example, if you installed another compiler (e.g. gcc from brew). Setting SDKROOT became so common that it might be a good idea to add it to ~/.bash_profile.