Issue 4950 - Add -fpermissive to allow building on recent gcc.This is caused by V8 code.Possibly…

common.gypi

 {
   'variables': {
     'visibility%': 'hidden',
     'library%': 'static_library',
     'component%': '',
     'want_separate_host_toolset': 0,
     'v8_optimized_debug': 0,
     'v8_enable_i18n_support': 0,
   },
 
   'conditions': [
     ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris" \
        or OS=="netbsd" or OS=="android"', {
       'target_defaults': {
-        # remove the -fpermissive when a newer v8 is used
-        # unless it is still required.
+        # V8 headers cause a build error on recent gcc.
+        # Adding -fpermissive to solve this.
+        # See https://issues.adblockplus.org/ticket/4950
+        # We might be able to do without after upgrading V8.
         'cflags': [ '-Wall', '-W', '-Wno-unused-parameter',
                     '-Wnon-virtual-dtor', '-pthread', '-fno-rtti',
                     '-pedantic', '-std=c++0x', '-fexceptions', '-fpermissive' ],
         'cflags!': [ '-Werror', ],
         'ldflags': [ '-pthread', ],
       },
     }],
     ['OS=="mac"', {
       'xcode_settings': {
         'CLANG_CXX_LANGUAGE_STANDARD': 'c++11',
@@ skipping 17 matching lines @@
     'msvs_cygwin_shell': 0,
     'target_conditions': [[
       'OS=="mac" and _type=="executable"', {
         'xcode_settings': {
           'OTHER_LDFLAGS': ['-stdlib=libc++'],
         },
       }
     ]],
   }
 }