[libc][math] Refactor exp implementation to header-only in src/__support/math folder.

Author: bassiounix

libc/shared/math.h

@@ -21,5 +21,6 @@
 #include "math/ldexpf.h"
 #include "math/ldexpf128.h"
 #include "math/ldexpf16.h"
+#include "math/exp.h"
 
 #endif // LLVM_LIBC_SHARED_MATH_H

libc/src/math/generic/common_constants.h

@@ -13,6 +13,8 @@
 #include "src/__support/macros/config.h"
 #include "src/__support/math/exp_constants.h"
 #include "src/__support/number_pair.h"
+#include "src/__support/math/exp_constants.h"
+
 
 namespace LIBC_NAMESPACE_DECL {