Added first example for libcurl NativeCall from farabi6 repo

test_curl.p6

@@ -0,0 +1,37 @@
+#!/usr/bin/env perl6
+use v6;
+
+use NativeCall;
+
+constant LIB = 'libcurl.so';
+
+sub curl_easy_init() returns OpaquePointer is native(LIB) { ... };
+sub curl_easy_cleanup(OpaquePointer)      is native(LIB) { ... };
+sub curl_easy_setopt(OpaquePointer, int, Str) is native(LIB) { ... };
+sub curl_easy_perform(OpaquePointer) returns int is native(LIB) { ... };
+sub curl_easy_strerror(int) returns Str is native(LIB) { ... };
+
+constant CURLOPT_URL = 10002;
+constant CURLE_OK    = 0;
+
+my $curl;
+my $res;
+
+$curl = curl_easy_init;
+if $curl {
+    curl_easy_setopt($curl, CURLOPT_URL, "http://example.com");
+
+    # Perform the request, res will get the return code
+    $res = curl_easy_perform($curl);
+
+    # Check for errors
+    if $res != CURLE_OK {
+      say "Error: curl_easy_perform() failed: {curl_easy_strerror($res)}\n";
+ 	} else {
+		say "Got a response!";
+	}
+	say "libcurl initialized!";
+
+    # always cleanup 
+    curl_easy_cleanup($curl);
+}