math: move trivial x86-family sqrt functions to C with inline asm

src/math/i386/sqrtl.c

+#include <math.h>
+
+long double sqrtl(long double x)
+{
+	__asm__ ("fsqrt" : "+t"(x));
+	return x;
+}

src/math/i386/sqrtl.s

-.global sqrtl
-.type sqrtl,@function
-sqrtl:	fldt 4(%esp)
-	fsqrt
-	ret

src/math/x86_64/sqrt.c

+#include <math.h>
+
+double sqrt(double x)
+{
+	__asm__ ("sqrtsd %1, %0" : "=x"(x) : "x"(x));
+	return x;
+}

src/math/x86_64/sqrt.s

-.global sqrt
-.type sqrt,@function
-sqrt:	sqrtsd %xmm0, %xmm0
-	ret

src/math/x86_64/sqrtf.c

+#include <math.h>
+
+float sqrtf(float x)
+{
+	__asm__ ("sqrtss %1, %0" : "=x"(x) : "x"(x));
+	return x;
+}

src/math/x86_64/sqrtf.s

-.global sqrtf
-.type sqrtf,@function
-sqrtf:  sqrtss %xmm0, %xmm0
-	ret

src/math/x86_64/sqrtl.c

+#include <math.h>
+
+long double sqrtl(long double x)
+{
+	__asm__ ("fsqrt" : "+t"(x));
+	return x;
+}

src/math/x86_64/sqrtl.s

-.global sqrtl
-.type sqrtl,@function
-sqrtl:	fldt 8(%rsp)
-	fsqrt
-	ret