fix dupblicate cgo import, use double instead of Float64 in C function return (#3391)

Signed-off-by: Ahmed Abdulraziq <ahmed.khaled.abdulraziq@gmail.com>

collector/filesystem_macos.go

@@ -20,8 +20,13 @@ package collector
 #cgo CFLAGS: -x objective-c
 #cgo LDFLAGS: -framework Foundation
 #import <Foundation/Foundation.h>
-Float64 purgeable(char *path) {
-  Float64 value = -1.0f;
+#include <sys/param.h>
+#include <sys/ucred.h>
+#include <sys/mount.h>
+#include <stdio.h>
+
+double purgeable(char *path) {
+  double value = -1.0f;
 
   @autoreleasepool {
     NSError *error = nil;
@@ -49,14 +54,6 @@ import (
 	"unsafe"
 )
 
-/*
-#include <sys/param.h>
-#include <sys/ucred.h>
-#include <sys/mount.h>
-#include <stdio.h>
-*/
-import "C"
-
 const (
 	defMountPointsExcluded = "^/(dev)($|/)"
 	defFSTypesExcluded     = "^devfs$"

collector/meminfo_darwin.go

@@ -52,7 +52,7 @@ func (c *meminfoCollector) getMemInfo() (map[string]float64, error) {
 		&infoCount,
 	)
 	if ret != C.KERN_SUCCESS {
-		return nil, fmt.Errorf("Couldn't get memory statistics, host_statistics returned %d", ret)
+		return nil, fmt.Errorf("couldn't get memory statistics, host_statistics returned %d", ret)
 	}
 	totalb, err := unix.Sysctl("hw.memsize")
 	if err != nil {