[libc++] Granularize some more type_traits

Reviewed By: ldionne, #libc

Spies: libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D128948

NOKEYCHECK=True
GitOrigin-RevId: b7aa9c4ac8e7a2736125109deeb0be8b1f41f852
diff --git a/include/math.h b/include/math.h
index 7d553e7..0ec584a 100644
--- a/include/math.h
+++ b/include/math.h
@@ -305,6 +305,7 @@
 // back to C++ linkage before including these C++ headers.
 extern "C++" {
 
+#include <__type_traits/promote.h>
 #include <limits>
 #include <stdlib.h>
 #include <type_traits>