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 92db5ff79dd1a9ca6b249f9fcc3ae356a7092e25..197c4f2b824d50e4e9d23e6f81960e3ad6f60df1 100644
--- a/build/linux/system.gyp
+++ b/build/linux/system.gyp
@@ -743,7 +743,10 @@
           },
           '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\')',
             ],
           },
         }],