libc: shut up compiler false positive in gamma functions

Found with mode=release.

libc/math/lgamma_r.c

@@ -197,7 +197,7 @@ static double sin_pi(double x)
 
 double __lgamma_r(double x, int *signgamp)
 {
-	double t,y,z,nadj,p,p1,p2,p3,q,r,w;
+	double t,y,z,nadj=0,p,p1,p2,p3,q,r,w;
 	int32_t hx;
 	int i,lx,ix;
 

libc/math/lgammaf_r.c

@@ -132,7 +132,7 @@ static float sin_pif(float x)
 
 float __lgammaf_r(float x, int *signgamp)
 {
-	float t,y,z,nadj,p,p1,p2,p3,q,r,w;
+	float t,y,z,nadj=0,p,p1,p2,p3,q,r,w;
 	int32_t hx;
 	int i,ix;
 

libc/math/lgammal.c

@@ -260,7 +260,7 @@ static long double sin_pi(long double x)
 }
 
 long double __lgammal_r(long double x, int *sg) {
-	long double t, y, z, nadj, p, p1, p2, q, r, w;
+	long double t, y, z, nadj = 0, p, p1, p2, q, r, w;
 	int i, ix;
 	uint32_t se, i0, i1;