Make sure the 'use_system_*' variables are actually visible in the relevant gyp files.

BUG=29738

Review URL: http://codereview.chromium.org/479005

git-svn-id: http://src.chromium.org/svn/trunk/src/build@34195 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -44,20 +44,6 @@
           # hosts should pass an explicit target_arch to gyp.
           'target_arch%':
             '<!(uname -m | sed -e "s/i.86/ia32/;s/x86_64/x64/;s/arm.*/arm/")',
-
-          # On Linux, we use the system versions of several libraries. We end
-          # up pulling these in as .so's anyway since they are already in our
-          # transitive closure due to GTK.
-          'use_system_zlib': 1,
-          'use_system_libjpeg': 1,
-          'use_system_bzip2': 1,
-          'use_system_libpng': 1,
-          'use_system_libjpeg': 1,
-          'use_system_libxslt': 1,
-
-          # We use our own copy of libssl, although we still need to link
-          # against the rest of NSS.
-          'use_system_ssl': 0,
         }, {  # OS!="linux"
           'target_arch%': 'ia32',
         }],

install-build-deps.sh

@@ -111,9 +111,9 @@ fi
 # Packages need for development
 dev_list="apache2 bison fakeroot flex g++ g++-multilib gperf libapache2-mod-php5
           libasound2-dev libcairo2-dev libgconf2-dev libglib2.0-dev
-          libgtk2.0-dev libnspr4-dev libnss3-dev libsqlite3-dev lighttpd
-          msttcorefonts patch perl php5-cgi pkg-config python rpm subversion
-          wdiff"
+          libgtk2.0-dev libjpeg62-dev libnspr4-dev libnss3-dev libsqlite3-dev
+          libxslt1-dev lighttpd msttcorefonts patch perl php5-cgi pkg-config
+          python rpm subversion wdiff"
 
 # Full list of required run-time libraries
 lib_list="libatk1.0-0 libc6 libasound2 libcairo2 libexpat1

linux/system.gyp

@@ -13,11 +13,19 @@
         'pkg-config': 'pkg-config'
       },
     }],
+    [ 'OS=="linux"', {
+      'variables': {
+        # We use our own copy of libssl, although we still need to link against
+        # the rest of NSS.
+        'use_system_ssl%': 0,
+      },
+    }, {  # OS!="linux"
+      'variables': {
+        'use_system_ssl%': 1,
+      },
+    }],
   ],
 
-  'variables': {
-    'use_system_ssl%': 1,
-  },
 
   'targets': [
     {