Reintroducing MallocHooks changes with fix for hooks being called when in execvpe after a fork whil…

runtime/vm/vm.gypi

Index: runtime/vm/vm.gypi
diff --git a/runtime/vm/vm.gypi b/runtime/vm/vm.gypi
index 1371285b1ee28c42814071b01ae2f5b962f82f22..a8c0e74ac4b04cbf916dea3ac8929de966de5729 100644
--- a/runtime/vm/vm.gypi
+++ b/runtime/vm/vm.gypi
@@ -61,13 +61,6 @@
             ],
           },
         }],
-        # The following condition should be kept in sync with the corresponding
-        # configurations in runtime/bin/bin.gypi.
-	['OS == "linux" and asan == 0 and msan == 0 and tsan == 0', {
-          'defines': [
-            'DART_USE_TCMALLOC'
-          ],
-        }],
         ['OS=="android" and _toolset=="host"', {
           'link_settings': {
             'libraries': [
@@ -112,13 +105,6 @@
             ],
           },
         }],
-        # The following condition should be kept in sync with the corresponding
-        # configurations in runtime/bin/bin.gypi.
-        ['OS == "linux" and asan == 0 and msan == 0 and tsan == 0', {
-          'defines': [
-            'DART_USE_TCMALLOC'
-          ],
-        }],
         ['OS=="android" and _toolset=="host"', {
           'link_settings': {
             'libraries': [
@@ -163,13 +149,6 @@
             ],
           },
         }],
-        # The following condition should be kept in sync with the corresponding
-        # configurations in runtime/bin/bin.gypi.
-        ['OS == "linux" and asan == 0 and msan == 0 and tsan == 0', {
-          'defines': [
-            'DART_USE_TCMALLOC'
-          ],
-        }],
         ['OS=="android" and _toolset=="host"', {
           'link_settings': {
             'libraries': [
@@ -215,13 +194,6 @@
             ],
           },
         }],
-        # The following condition should be kept in sync with the corresponding
-        # configurations in runtime/bin/bin.gypi.
-        ['OS == "linux" and asan == 0 and msan == 0 and tsan == 0', {
-          'defines': [
-            'DART_USE_TCMALLOC'
-          ],
-        }],
         ['OS=="android" and _toolset=="host"', {
           'link_settings': {
             'libraries': [