Redefine is_linux to not include Android in the GN build.

tools/gn/secondary/third_party/libxml/BUILD.gn

Index: tools/gn/secondary/third_party/libxml/BUILD.gn
diff --git a/tools/gn/secondary/third_party/libxml/BUILD.gn b/tools/gn/secondary/third_party/libxml/BUILD.gn
index 96024eabcd67db87fb225257f16d542b5aa35ca5..aa6936e9f18557754a28a9eefe12016c4e1a140c 100644
--- a/tools/gn/secondary/third_party/libxml/BUILD.gn
+++ b/tools/gn/secondary/third_party/libxml/BUILD.gn
@@ -4,7 +4,7 @@
 
 # Define an "os_include" variable that points at the OS-specific generated
 # headers.  These were generated by running the configure script offline.
-if (is_linux) {
+if (is_linux || is_android) {
   os_include = "linux"
 } else if (is_mac || is_ios) {
   os_include = "mac"
@@ -155,9 +155,6 @@ static_library("libxml") {
     cflags_c = [
       "/wd4101",  # Unreferenced local variable.
     ]
-  } else if (is_linux) {
-    # We need dl for dlopen() and friends.
-    libs = [ "dl" ]
   } else if (is_mac || is_android) {
     # http://www.xmlsoft.org/threads.html says that this is required when using
     # libxml from several threads, which can possibly happen in chrome. On