Fix linker warning on build with target_arch=ia32.

build/linux/system.gyp

Index: build/linux/system.gyp
diff --git a/build/linux/system.gyp b/build/linux/system.gyp
index 7911ae9b4d763fd5f7b5cf71369c586c5fc823fc..a9eb2e9aa6edd5353c25606d27a103e595a06939 100644
--- a/build/linux/system.gyp
+++ b/build/linux/system.gyp
@@ -741,7 +741,10 @@
           },
           'link_settings': {
             'libraries': [
-              '<!@(libgcrypt-config --libs)',
+              # libgcrypt-config does not support --libs-only-l options,
+              # and the result contains -L options, which shouldn't be in
+              # the entries of 'libraries'. So filter them out.
+              '<!@(libgcrypt-config --libs | sed -e \'s/-L[^ ]*//g\')',
             ],
           },
         }],