Extend skip section

The test requires some untrivial amount of RAM. Added a simple check for
the system free RAM to avoid false positive fails.

Author: weltling

ext/gmp/tests/gmp_setbit_long.phpt

@@ -4,6 +4,21 @@ gmp_setbit() with large index
 <?php if (!extension_loaded("gmp")) print "skip"; ?>
 <?php if (PHP_INT_SIZE != 8) die("skip this test is for 64bit platform only"); ?>
 <?php if (getenv("SKIP_SLOW_TESTS")) die("skip slow test"); ?>
+<?php
+	/* This test requires about 8G RAM which likely not to be present on an arbitrary CI. */
+	if (!file_exists("/proc/meminfo")) {
+		die("skip cannot determine free memory amount.");
+	}
+	$s = file_get_contents("/proc/meminfo");
+	$free = 0;
+	if (preg_match(",MemFree:\s+(\d+)\s+kB,", $s, $m)) {
+		/* Got amount in kb. */
+		$free = $m[1]/1024/1024;
+	}
+	if ($free < 8) {
+		die("skip not enough free RAM.");
+	}
+?>
 --FILE--
 <?php
 
@@ -23,4 +38,4 @@ FFFFFFFFF
 3FFFFFFFFF
 
 Warning: gmp_setbit(): Index must be less than %d * %d in %s/gmp_setbit_long.php on line %d
-Done
+Done