Use boost-for-react-native CocoaPod

Summary:
Use the same header-only distribution of Boost that Android and the automatic ios-install-third-party.sh script uses. Greatly speeds up `pod install`, even when the distribution was already cached.

The dependency tree looks like this:

* React
  * cxxreact subspec
    * **Boost** (versioned, 1.63.0)
    * Folly
      * **Boost** (any version, will resolve to 1.63.0 from above)

Alternative implementation of PR #16756. Fixes issue #16381.

(same as #16756)
* Install react-native via Cocoapods (or move a helloWorld react-native application over to use Cocoapods for dependency management)
* Add CxxBridge instead of BatchedBridge to your Podfile
* run pod install
* run react-native run-ios

[Add boost.podspec speed up download time & reduce size of the package](#16756)

[IOS] [BUGFIX] [third-party-podspecs] - optimize CocoaPods installation (Boost distribution)
Closes #17476

Differential Revision: D6746095

Pulled By: hramos

fbshipit-source-id: 55b2b5a698691f7fca0bf4c31c4376c2b9eb5379

Author: CFKevinRef

React.podspec

@@ -139,13 +139,13 @@ Pod::Spec.new do |s|
   s.subspec "cxxreact" do |ss|
     ss.dependency             "React/jschelpers"
     ss.dependency             "React/jsinspector"
-    ss.dependency             "boost"
+    ss.dependency             "boost-for-react-native", "1.63.0"
     ss.dependency             "Folly", "2016.09.26.00"
     ss.compiler_flags       = folly_compiler_flags
     ss.source_files         = "ReactCommon/cxxreact/*.{cpp,h}"
     ss.exclude_files        = "ReactCommon/cxxreact/SampleCxxModule.*"
     ss.private_header_files = "ReactCommon/cxxreact/*.h"
-    ss.pod_target_xcconfig  = { "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/ReactCommon\" \"$(PODS_ROOT)/boost\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/Folly\"" }
+    ss.pod_target_xcconfig  = { "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/ReactCommon\" \"$(PODS_ROOT)/boost-for-react-native\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/Folly\"" }
   end
 
   s.subspec "ART" do |ss|

third-party-podspecs/Folly.podspec

@@ -8,7 +8,7 @@ Pod::Spec.new do |spec|
   spec.source = { :git => 'https://github.com/facebook/folly.git',
                   :tag => "v#{spec.version}" }
   spec.module_name = 'folly'
-  spec.dependency 'boost'
+  spec.dependency 'boost-for-react-native'
   spec.dependency 'DoubleConversion'
   spec.dependency 'GLog'
   spec.compiler_flags = '-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1'
@@ -28,7 +28,7 @@ Pod::Spec.new do |spec|
   spec.libraries           = "stdc++"
   spec.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
                                "CLANG_CXX_LANGUAGE_STANDARD" => "c++14",
-                               "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\" \"$(PODS_ROOT)/boost\" \"$(PODS_ROOT)/DoubleConversion\"" }
+                               "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\" \"$(PODS_ROOT)/boost-for-react-native\" \"$(PODS_ROOT)/DoubleConversion\"" }
 
   # Pinning to the same version as React.podspec.
   spec.platforms = { :ios => "8.0", :tvos => "9.2" }

third-party-podspecs/GLog.podspec

@@ -10,6 +10,7 @@ Pod::Spec.new do |spec|
   spec.source = { :git => 'https://github.com/google/glog.git',
                   :tag => "v#{spec.version}" }
   spec.module_name = 'glog'
+  spec.header_dir = 'glog'
   spec.source_files = 'src/glog/*.h',
                       'src/demangle.cc',
                       'src/logging.cc',