[testsuite] Require c99_runtime for pr79800.c

2017-04-07  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/testsuite/
    * gcc.dg/tree-ssa/pr79800.c: Require c99_runtime.

From-SVN: r246758

gcc/testsuite/ChangeLog

+2017-04-07  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	* gcc.dg/tree-ssa/pr79800.c: Require c99_runtime.
+
 2017-04-07  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/80334

gcc/testsuite/gcc.dg/tree-ssa/pr79800.c

 /* PR 79800 - wrong snprintf result range with precision in a narrow
    negative-positive range
-   { dg-do "run" }
+   { dg-do "run" { target c99_runtime } }
    { dg-options "-O2 -Wall" } */
 
 #define FMT "%.*a"