catastrophic error: cannot open source file "stdio.h"

While compiling and linking your C/C++ code against the ParaMonte libraries via the Intel C/C++ compilers on macOS, you may receive a compiler error message similar to the following,

catastrophic error: cannot open source file "stdio.h"

or,

catastrophic error: cannot open source file "math.h"

or,

xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

Taking the following steps to install the macOS Command Line Tools and then agreeing with its license terms may fix this issue. Open a Bash command prompt and type the following and run them,

xcode-select --install # Install the Command Line Tools in case you do not have it already.
sudo xcode-select --switch /Library/Developer/CommandLineTools # Enable command line tools

or, alternatively, via the full Xcode.app (if it is already installed on your system),

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer # change the path if Xcode is installed somewhere else.

You will have to also agree with the Xcode license terms, which requires running the following command on the Bash terminal,

sudo xcodebuild -license accept