build: include postmortem symbols on linux

Previously we were building the symbols, but the linker was garbage
collecting the symbols because they weren't used. Inform the linker
that we want to keep all symbols from v8 around.

common.gypi

@@ -79,10 +79,12 @@
             ],
           }],
           ['OS=="solaris"', {
-            'cflags': [ '-fno-omit-frame-pointer' ],
             # pull in V8's postmortem metadata
             'ldflags': [ '-Wl,-z,allextract' ]
           }],
+          ['OS!="mac" and OS!="win"', {
+            'cflags': [ '-fno-omit-frame-pointer' ],
+          }],
         ],
         'msvs_settings': {
           'VCCLCompilerTool': {

node.gyp

@@ -290,6 +290,12 @@
             'PLATFORM="sunos"',
           ],
         }],
+        [
+          'OS=="linux"', {
+            'ldflags': [
+              '-Wl,--whole-archive <(PRODUCT_DIR)/obj.target/deps/v8/tools/gyp/libv8_base.a -Wl,--no-whole-archive',
+            ],
+        }],
       ],
       'msvs_settings': {
         'VCLinkerTool': {