I want to use gcc and gcn in 2 separate steps to compile and link C program

I want to use gcc and gcn in 2 separate steps to compile and link C program.The problem I got is that linker does not find basic C functions like pop, push, isValid, etc,etc,etcI do not want to use sofisticated packages at this point like Xcode available on my platform.When trying to run gcc :gcc -v function#1.c -o function#1

I got back from the system:

xcrun: error: active developer path ("/Applications/Xcode.app/Contents/Developer") does not existUse sudo xcode-select --switch path/to/Xcode.app to specify the Xcode that you wish to use for command line developer tools, or use xcode-select --install to install the standalone command line developer tools.See man xcode-select for more details.

Any help is greatly appreciated.