Removed dead ceiling function.

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 923cd8700ed9a062c8ed8ad7a505da253ae084dd..879dcc81484196905fa82a9860e9e4c03b264bc2 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -288,12 +288,6 @@ void OS::DebugBreak() {
 // ----------------------------------------------------------------------------
 // Math functions
 
-double ceiling(double x) {
-  // Correct buggy 'ceil' on some systems (i.e. FreeBSD, OS X 10.5)
-  return (-1.0 < x && x < 0.0) ? -0.0 : ceil(x);
-}
-
-
 double modulo(double x, double y) {
   return fmod(x, y);
 }