Build on Linux with shared libraries (significant chunks courtesy craigsch):...

build/common.gypi

 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     # .gyp files should set chromium_code to 1 if they build Chromium-specific
     # code, as opposed to external code.  This variable is used to control
     # such things as the set of warnings to enable, and whether warnings are
     # treated as errors.
@@ skipping 201 matching lines @@
           # Note:  $_LIBDIRFLAGS comes before ${LINK,SHLINK,LDMODULE}FLAGS
           # so that we prefer our own built libraries (e.g. -lpng) to
           # system versions of libraries that pkg-config might turn up.
           # TODO(sgk): investigate handling this not by re-ordering the
           # flags this way, but by adding a hook to use the SCons
           # ParseFlags() option on the output from pkg-config.
           'LINKCOM': [['$FLOCK_LINK', '-o', '$TARGET', '$_LIBDIRFLAGS', '$LINKFLAGS', '$SOURCES', '-Wl,--start-group', '$_LIBFLAGS', '-Wl,--end-group']],
           'SHLINKCOM': [['$FLOCK_SHLINK', '-o', '$TARGET', '$_LIBDIRFLAGS', '$SHLINKFLAGS', '$SOURCES', '-Wl,--start-group', '$_LIBFLAGS', '-Wl,--end-group']],
           'LDMODULECOM': [['$FLOCK_LDMODULE', '-o', '$TARGET', '$_LIBDIRFLAGS', '$LDMODULEFLAGS', '$SOURCES', '-Wl,--start-group', '$_LIBFLAGS', '-Wl,--end-group']],
           'IMPLICIT_COMMAND_DEPENDENCIES': 0,
+          # -rpath is only used when building with shared libraries.
+          'conditions': [
+            [ 'library=="shared_library"', {
+              'RPATH': '$LIB_DIR',
+            }],
+          ],
         },
         'scons_import_variables': [
           'CC',
           'CXX',
           'LINK',
         ],
         'scons_propagate_variables': [
           'CC',
           'CCACHE_DIR',
           'CXX',
@@ skipping 186 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }