Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
Whoeaaa!  There's something fishy going on here.
You have a look and see if you detect anything uncanny:
*******************************************************
gcc _autotst.c -o _autotst
_autotst.c:1:1: error: return type defaults to ‘int’ [-Wimplicit-int]
    1 | main()
      | ^~~~
::::
cc _autotst.c -o _autotst
_autotst.c:1:1: error: return type defaults to ‘int’ [-Wimplicit-int]
    1 | main()
      | ^~~~
::::
gcc _autotst.c -o _autotst
_autotst.c:1:1: error: return type defaults to ‘int’ [-Wimplicit-int]
    1 | main()
      | ^~~~
::::
*******************************************************
I suggest you take a look at the definition of CFLAGS* and CC
in the Makefile before you try make again.
The log snip shows error during configure phase where the script tries to autodetect compiler and it abilities.