fix #25131, OS_Guess warnings

pear/OS/Guess.php

@@ -167,7 +167,7 @@ class OS_Guess
         $cpp = popen("/usr/bin/cpp $tmpfile", "r");
         $major = $minor = 0;
         while ($line = fgets($cpp, 1024)) {
-            if ($line{0} == '#') {
+            if ($line{0} == '#' || trim($line) == '') {
                 continue;
             }
             if (list($major, $minor) = explode(' ', trim($line))) {

pear/package-PEAR.xml

@@ -41,6 +41,8 @@
     <date>2003-08-??</date>
     <state>stable</state>
     <notes>
+* Fixed #25131 - OS_Guess warnings on empty lines from
+  popen(&quot;/usr/bin/cpp $tmpfile&quot;, &quot;r&quot;);
 * Fixed #25117 - MD5 checksum should be case-insensitive
 * Fixed static calls to PEAR error-handling methods in classes (Greg)
 * Added ability to use a static method callback for error-handling, and removed