[libxml2] Use __linux__ macro in generated code

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 03a238f954ed2959e9eacb011872779e6e77ab5d
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Sep 29 13:00:50 2017 +0200

    Use __linux__ macro in generated code

 .travis.yml        |    3 +--
 doc/elfgcchack.xsl |    2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/.travis.yml b/.travis.yml
index 6055b9a..e14375f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,8 +8,7 @@ addons:
 matrix:
   include:
     # Try to emulate a C89 compiler on a POSIX system by disabling as many
-    # GNU extensions as possible. -Dlinux is required to make the weak
-    # pthread symbols work.
+    # GNU extensions as possible.
     - compiler: gcc
       env: CFLAGS="-O2 -std=c89 -D_POSIX_C_SOURCE=200809L"
     # clang with AddressSanitizer and UndefinedBehaviorSanitizer.
diff --git a/doc/elfgcchack.xsl b/doc/elfgcchack.xsl
index 9b1a9bc..8dd5c6a 100644
--- a/doc/elfgcchack.xsl
+++ b/doc/elfgcchack.xsl
@@ -18,7 +18,7 @@
 #ifdef IN_LIBXML
 #ifdef __GNUC__
 #ifdef PIC
-#ifdef linux
+#ifdef __linux__
 #if (__GNUC__ == 3 &amp;&amp; __GNUC_MINOR__ >= 3) || (__GNUC__ > 3)
 
 #include "libxml/c14n.h"