libzigc/math: Implement lrint

The changes were tested by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib

$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=lrint -fqemu -fwasmtime --summary line
Build Summary: 737/737 steps succeeded
```

lib/c/math.zig

@@ -66,6 +66,7 @@ comptime {
         symbol(&finitef, "finitef");
         symbol(&frexp, "frexp");
         symbol(&hypot, "hypot");
+        symbol(&lrint, "lrint");
         symbol(&modf, "modf");
         symbol(&pow, "pow");
         symbol(&pow10, "pow10");
@@ -229,6 +230,10 @@ fn isnanl(x: c_longdouble) callconv(.c) c_int {
     return if (math.isNan(x)) 1 else 0;
 }
 
+fn lrint(x: f64) callconv(.c) c_long {
+    return @intFromFloat(rint(x));
+}
+
 fn modfGeneric(comptime T: type, x: T, iptr: *T) T {
     if (math.isNegativeInf(x)) {
         iptr.* = -math.inf(T);

lib/libc/musl/src/math/aarch64/lrint.c

@@ -1,10 +0,0 @@
-#include <math.h>
-
-long lrint(double x)
-{
-	long n;
-	__asm__ (
-		"frintx %d1, %d1\n"
-		"fcvtzs %x0, %d1\n" : "=r"(n), "+w"(x));
-	return n;
-}

lib/libc/musl/src/math/i386/lrint.c

@@ -1,8 +0,0 @@
-#include <math.h>
-
-long lrint(double x)
-{
-	long r;
-	__asm__ ("fistpl %0" : "=m"(r) : "t"(x) : "st");
-	return r;
-}

lib/libc/musl/src/math/lrint.c

@@ -1,72 +0,0 @@
-#include <limits.h>
-#include <fenv.h>
-#include <math.h>
-#include "libm.h"
-
-/*
-If the result cannot be represented (overflow, nan), then
-lrint raises the invalid exception.
-
-Otherwise if the input was not an integer then the inexact
-exception is raised.
-
-C99 is a bit vague about whether inexact exception is
-allowed to be raised when invalid is raised.
-(F.9 explicitly allows spurious inexact exceptions, F.9.6.5
-does not make it clear if that rule applies to lrint, but
-IEEE 754r 7.8 seems to forbid spurious inexact exception in
-the ineger conversion functions)
-
-So we try to make sure that no spurious inexact exception is
-raised in case of an overflow.
-
-If the bit size of long > precision of double, then there
-cannot be inexact rounding in case the result overflows,
-otherwise LONG_MAX and LONG_MIN can be represented exactly
-as a double.
-*/
-
-#if LONG_MAX < 1U<<53 && defined(FE_INEXACT)
-#include <float.h>
-#include <stdint.h>
-#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
-#define EPS DBL_EPSILON
-#elif FLT_EVAL_METHOD==2
-#define EPS LDBL_EPSILON
-#endif
-#ifdef __GNUC__
-/* avoid stack frame in lrint */
-__attribute__((noinline))
-#endif
-static long lrint_slow(double x)
-{
-	#pragma STDC FENV_ACCESS ON
-	int e;
-
-	e = fetestexcept(FE_INEXACT);
-	x = rint(x);
-	if (!e && (x > LONG_MAX || x < LONG_MIN))
-		feclearexcept(FE_INEXACT);
-	/* conversion */
-	return x;
-}
-
-long lrint(double x)
-{
-	uint32_t abstop = asuint64(x)>>32 & 0x7fffffff;
-	uint64_t sign = asuint64(x) & (1ULL << 63);
-
-	if (abstop < 0x41dfffff) {
-		/* |x| < 0x7ffffc00, no overflow */
-		double_t toint = asdouble(asuint64(1/EPS) | sign);
-		double_t y = x + toint - toint;
-		return (long)y;
-	}
-	return lrint_slow(x);
-}
-#else
-long lrint(double x)
-{
-	return rint(x);
-}
-#endif

lib/libc/musl/src/math/powerpc64/lrint.c

@@ -1,16 +0,0 @@
-#include <math.h>
-
-#ifdef _ARCH_PWR5X
-
-long lrint(double x)
-{
-	long n;
-	__asm__ ("fctid %0, %1" : "=d"(n) : "d"(x));
-	return n;
-}
-
-#else
-
-#include "../lrint.c"
-
-#endif

lib/libc/musl/src/math/x32/lrint.s

@@ -1,5 +0,0 @@
-.global lrint
-.type lrint,@function
-lrint:
-	cvtsd2si %xmm0,%rax
-	ret

lib/libc/musl/src/math/x86_64/lrint.c

@@ -1,8 +0,0 @@
-#include <math.h>
-
-long lrint(double x)
-{
-	long r;
-	__asm__ ("cvtsd2si %1, %0" : "=r"(r) : "x"(x));
-	return r;
-}

src/libs/musl.zig

@@ -787,7 +787,6 @@ const src_files = [_][]const u8{
     "musl/src/math/aarch64/llrintf.c",
     "musl/src/math/aarch64/llround.c",
     "musl/src/math/aarch64/llroundf.c",
-    "musl/src/math/aarch64/lrint.c",
     "musl/src/math/aarch64/lrintf.c",
     "musl/src/math/aarch64/lround.c",
     "musl/src/math/aarch64/lroundf.c",
@@ -860,7 +859,6 @@ const src_files = [_][]const u8{
     "musl/src/math/i386/log1p.s",
     "musl/src/math/i386/log2l.s",
     "musl/src/math/i386/logl.s",
-    "musl/src/math/i386/lrint.c",
     "musl/src/math/i386/lrintf.c",
     "musl/src/math/i386/lrintl.c",
     "musl/src/math/i386/remainder.c",
@@ -910,7 +908,6 @@ const src_files = [_][]const u8{
     "musl/src/math/logbf.c",
     "musl/src/math/logbl.c",
     "musl/src/math/logl.c",
-    "musl/src/math/lrint.c",
     "musl/src/math/lrintf.c",
     "musl/src/math/lrintl.c",
     "musl/src/math/lround.c",
@@ -940,7 +937,6 @@ const src_files = [_][]const u8{
     "musl/src/math/pow_data.c",
     "musl/src/math/powerpc64/fma.c",
     "musl/src/math/powerpc64/fmaf.c",
-    "musl/src/math/powerpc64/lrint.c",
     "musl/src/math/powerpc64/lrintf.c",
     "musl/src/math/powerpc64/lround.c",
     "musl/src/math/powerpc64/lroundf.c",
@@ -1017,7 +1013,6 @@ const src_files = [_][]const u8{
     "musl/src/math/x32/logl.s",
     "musl/src/math/x32/lrintf.s",
     "musl/src/math/x32/lrintl.s",
-    "musl/src/math/x32/lrint.s",
     "musl/src/math/x32/remainderl.s",
     "musl/src/math/x32/rintl.s",
     "musl/src/math/x86_64/acosl.s",
@@ -1036,7 +1031,6 @@ const src_files = [_][]const u8{
     "musl/src/math/x86_64/log1pl.s",
     "musl/src/math/x86_64/log2l.s",
     "musl/src/math/x86_64/logl.s",
-    "musl/src/math/x86_64/lrint.c",
     "musl/src/math/x86_64/lrintf.c",
     "musl/src/math/x86_64/lrintl.c",
     "musl/src/math/x86_64/remainderl.c",

src/libs/wasi_libc.zig

@@ -732,7 +732,6 @@ const libc_top_half_src_files = [_][]const u8{
     "musl/src/math/logbf.c",
     "musl/src/math/logbl.c",
     "musl/src/math/logl.c",
-    "musl/src/math/lrint.c",
     "musl/src/math/lrintf.c",
     "musl/src/math/lrintl.c",
     "musl/src/math/lround.c",