Issue 6526 - show warnings about deprecated V8 API

Author: abby-sergz

Makefile

@@ -51,7 +51,7 @@ endif
 
 GYP_PARAMETERS=host_arch=${HOST_ARCH} OS=${TARGET_OS} target_arch=${ABP_TARGET_ARCH}
 ifneq "$(and ${LIBV8_LIB_DIR}, ${LIBV8_INCLUDE_DIR})" ""
-GYP_PARAMETERS+= libv8_lib_dir=${LIBV8_LIB_DIR} libv8_include_dir=${LIBV8_INCLUDE_DIR}
+GYP_PARAMETERS+= libv8_lib_dir=${LIBV8_LIB_DIR} libv8_include_dir=${LIBV8_INCLUDE_DIR} libv8_show_warnings=${libv8_show_warnings}
 else
 $(error "V8 directories are not specified")
 endif

README.md

@@ -313,3 +313,8 @@ You can lint the code using [ESLint](http://eslint.org).
 In order to set up ESLint and
 [configuration eslint-config-eyeo](https://hg.adblockplus.org/codingtools/file/tip/eslint-config-eyeo) you need [Node.js 7 or higher](https://nodejs.org/) and once it is installed please run `npm install` in the repository directory.
 
+In order to learn about the usage of deprecated V8 API please set `libv8_show_warnings` to `"true"` on *nix, e.g.
+
+    make libv8_show_warnings="true"
+
+or on Windows add it to `GYP_DEFINES`.

v8.gypi

@@ -15,4 +15,14 @@
       }]
     ]
   },
+  'target_defaults': {
+    'conditions': [[
+      'libv8_show_warnings=="true"', {
+        'defines': [
+          'V8_DEPRECATION_WARNINGS',
+          'V8_IMMINENT_DEPRECATION_WARNINGS'
+        ]
+      }
+    ]]
+  }
 }