I have learned Mainframe Programming at the university. I am preferring
openSUSE instead of z/OS. Therefore, I wanted to test gnu-cobol.

You can not compile any "Hello World" program with cobc at the moment.

Steps to reproduce:
1) Install gnu-cobol in openSUSE Tumbleweed on any 64Bit architecture (tested
on x86 and s390x)
2) Create a helloworld.cobol file with following content:
IDENTIFICATION DIVISION.
    PROGRAM-ID. HELLO-WORLD.
PROCEDURE DIVISION.
    DISPLAY 'Hello world!'.
    STOP RUN.

3) Run "cobc -x helloworld.cobol "
4) You will receive following error message:
helloworld.cobol:1: error: invalid indicator 'F' at column 7
helloworld.cobol:2: error: invalid indicator 'O' at column 7
helloworld.cobol:3: error: invalid indicator 'U' at column 7
helloworld.cobol:4: error: invalid indicator 'S' at column 7
helloworld.cobol:5: error: invalid indicator 'O' at column 7
helloworld.cobol:6: Fehler: PROGRAM-ID header missing


You can see in the code above, that the PROGRAM-ID exist in the second line.
Therefore, the compiler can not identify the headers correctly. The compiler
can go through the colums, what is correct. But there is a problem with the
headers.

5) I have used the Ubuntu tutorial for reformatting with "--free". Perhaps
there is a problem with the Cobol format:
Run "cobc -x --free helloworld.cobol"
6) You will receive this error message:
/tmp/cob41237_0.c:12:10: fatal error: libcob.h: No such file or directory
   12 | #include <libcob.h>
      |          ^~~~~~~~~~

This error message gives us the hint, that libcob.h can not be found. I took a
look into our spec file for gnu-cobol. libcob.h is listed in the file list
within the libcob package (part of gnu-cobol).

Tutorials for Non-Cobol-Programmers:
Used for the first error example:
https://fedoramagazine.org/getting-started-with-cobol-development-on-fedora-linux-33/
Used for the second error example:
https://www.thegeekstuff.com/2010/02/cobol-hello-world-example-how-to-write-compile-and-execute-cobol-program-on-linux-os/