fix unicode content parsing

lessc.inc.php

@@ -1647,6 +1647,14 @@ public function compile($string, $name = null) {
 		$locale = setlocale(LC_NUMERIC, 0);
 		setlocale(LC_NUMERIC, "C");
 
+        $internal_encoding = NULL;
+        // only if mbstring installed
+        if (function_exists('mb_orig_strlen')) {
+            $internal_encoding = ini_get('mbstring.internal_encoding');
+            if(!is_null($internal_encoding)){
+                ini_set('mbstring.internal_encoding', NULL);
+            }
+        }
 		$this->parser = $this->makeParser($name);
 		$root = $this->parser->parse($string);
 
@@ -1666,6 +1674,9 @@ public function compile($string, $name = null) {
 		$this->formatter->block($this->scope);
 		$out = ob_get_clean();
 		setlocale(LC_NUMERIC, $locale);
+        if(!is_null($internal_encoding)){
+            ini_set('mbstring.internal_encoding', $internal_encoding);
+        }
 		return $out;
 	}
 
@@ -2106,6 +2117,7 @@ public function __construct($lessc, $sourceName = null) {
 	}
 
 	public function parse($buffer) {
+
 		$this->count = 0;
 		$this->line = 1;
 
@@ -2126,6 +2138,7 @@ public function parse($buffer) {
 		$lastCount = $this->count;
 		while (false !== $this->parseChunk());
 
+
 		if ($this->count != strlen($this->buffer))
 			$this->throwError();
 

tests/inputs/utf_symbols.less

@@ -0,0 +1,15 @@
+ul {
+    li {
+        &:before {
+            content: "—";
+        }
+    }
+    &:after {
+        content: "©—©";
+    }
+}
+div {
+    &:before {
+        content: "Привет, мир!";
+    }
+}

tests/outputs/utf_symbols.css

@@ -0,0 +1,9 @@
+ul li:before {
+  content: "—";
+}
+ul:after {
+  content: "©—©";
+}
+div:before {
+  content: "Привет, мир!";
+}