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: 
sdl.c:717:16: error: implicit declaration of function âfabsfâ [-Wimplicit-function-declaration]
  717 |     float d0 = fabsf(fasp - asp);
      |                ^~~~~
This is compiler error. Function was used without previous declaration. This is not allowed in many compiled languages, like C. 