[style] Try to fix MSVC build
diff --git a/src/hb-style.cc b/src/hb-style.cc
index b6f31b5..6e27b59 100644
--- a/src/hb-style.cc
+++ b/src/hb-style.cc
@@ -26,6 +26,8 @@
 
 #ifndef HB_NO_STYLE
 
+#include <math.h>
+
 #include "hb-ot-var-avar-table.hh"
 #include "hb-ot-var-fvar-table.hh"
 #include "hb-ot-stat-table.hh"