fix loads of missing const in new libm, and some global vars (?!) in powl

src/math/log2l.c

@@ -69,7 +69,7 @@ long double log2l(long double x)
  * 1/sqrt(2) <= x < sqrt(2)
  * Theoretical peak relative error = 6.2e-22
  */
-static long double P[] = {
+static const long double P[] = {
  4.9962495940332550844739E-1L,
  1.0767376367209449010438E1L,
  7.7671073698359539859595E1L,
@@ -78,7 +78,7 @@ static long double P[] = {
  3.4258224542413922935104E2L,
  1.0747524399916215149070E2L,
 };
-static long double Q[] = {
+static const long double Q[] = {
 /* 1.0000000000000000000000E0,*/
  2.3479774160285863271658E1L,
  1.9444210022760132894510E2L,
@@ -94,13 +94,13 @@ static long double Q[] = {
  * 1/sqrt(2) <= x < sqrt(2)
  * Theoretical peak relative error = 6.16e-22
  */
-static long double R[4] = {
+static const long double R[4] = {
  1.9757429581415468984296E-3L,
 -7.1990767473014147232598E-1L,
  1.0777257190312272158094E1L,
 -3.5717684488096787370998E1L,
 };
-static long double S[4] = {
+static const long double S[4] = {
 /* 1.00000000000000000000E0L,*/
 -2.6201045551331104417768E1L,
  1.9361891836232102174846E2L,