Move header_mappings_dir one dir up so imports are like <RxLibrary/...>

Part of fixing https://github.com/grpc/grpc/issues/2192

templates/gRPC.podspec.template

@@ -43,7 +43,6 @@ def fix_header_name(name):
     split_name = split_name[1:]
   return '/'.join(split_name)
 %>
-
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
   s.version  = '0.6.0'
@@ -59,17 +58,19 @@ Pod::Spec.new do |s|
   s.osx.deployment_target = '10.8'
   s.requires_arc = true
 
+  objc_dir = 'src/objective-c'
+
   # Reactive Extensions library for iOS.
-  s.subspec 'RxLibrary' do |rs|
-    rs.source_files = 'src/objective-c/RxLibrary/*.{h,m}',
-                      'src/objective-c/RxLibrary/transformations/*.{h,m}',
-                      'src/objective-c/RxLibrary/private/*.{h,m}'
-    rs.private_header_files = 'src/objective-c/RxLibrary/private/*.h'
+  s.subspec 'RxLibrary' do |ss|
+    src_dir = "#{objc_dir}/RxLibrary"
+    ss.source_files = "#{src_dir}/*.{h,m}", "#{src_dir}/**/*.{h,m}"
+    ss.private_header_files = "#{src_dir}/private/*.h"
+    ss.header_mappings_dir = "#{objc_dir}"
   end
 
   # Core cross-platform gRPC library, written in C.
-  s.subspec 'C-Core' do |cs|
-    cs.source_files = \
+  s.subspec 'C-Core' do |ss|
+    ss.source_files = \
 % for lib in libs:
 % if lib.name in ("grpc", "gpr"):
 % for hdr in lib.get("headers", []):
@@ -84,7 +85,7 @@ Pod::Spec.new do |s|
 % endif
 % endfor
 
-    cs.private_header_files = \
+    ss.private_header_files = \
 % for lib in libs:
 % if lib.name in ("grpc", "gpr"):
 % for hdr in lib.get("headers", []):
@@ -93,11 +94,11 @@ Pod::Spec.new do |s|
 % endif
 % endfor
 
-    cs.header_mappings_dir = '.'
+    ss.header_mappings_dir = '.'
 
-    cs.requires_arc = false
-    cs.libraries = 'z'
-    cs.dependency 'OpenSSL', '~> 1.0.200'
+    ss.requires_arc = false
+    ss.libraries = 'z'
+    ss.dependency 'OpenSSL', '~> 1.0.200'
   end
 
   # This is a workaround for Cocoapods Issue #1437.
@@ -105,7 +106,7 @@ Pod::Spec.new do |s|
   # It needs to be here (top-level) instead of in the C-Core subspec because Cocoapods doesn't run
   # prepare_command's of subspecs.
   #
-  # TODO(jcanizales): Try out Todd Reed's solution at Issue #1437.
+  # TODO(jcanizales): Try out others' solutions at Issue #1437.
   s.prepare_command = <<-CMD
     # Move contents of include up a level to avoid manually specifying include paths
     cp -r "include/grpc" "."
@@ -130,25 +131,27 @@ Pod::Spec.new do |s|
   CMD
 
   # Objective-C wrapper around the core gRPC library.
-  s.subspec 'GRPCClient' do |gs|
-    gs.source_files = 'src/objective-c/GRPCClient/*.{h,m}',
-                      'src/objective-c/GRPCClient/private/*.{h,m}'
-    gs.private_header_files = 'src/objective-c/GRPCClient/private/*.h'
-    gs.compiler_flags = '-GCC_WARN_INHIBIT_ALL_WARNINGS', '-w'
+  s.subspec 'GRPCClient' do |ss|
+    src_dir = "#{objc_dir}/GRPCClient"
+    ss.source_files = "#{src_dir}/*.{h,m}", "#{src_dir}/**/*.{h,m}"
+    ss.private_header_files = "#{src_dir}/private/*.h"
+    ss.header_mappings_dir = "#{objc_dir}"
 
-    gs.dependency 'gRPC/C-Core'
-    gs.dependency 'gRPC/RxLibrary'
+    ss.dependency 'gRPC/C-Core'
+    ss.dependency 'gRPC/RxLibrary'
 
     # Certificates, to be able to establish TLS connections:
-    gs.resource_bundles = { 'gRPC' => ['etc/roots.pem'] }
+    ss.resource_bundles = { 'gRPC' => ['etc/roots.pem'] }
   end
 
   # RPC library for ProtocolBuffers, based on gRPC
-  s.subspec 'ProtoRPC' do |ps|
-    ps.source_files = 'src/objective-c/ProtoRPC/*.{h,m}'
-
-    ps.dependency 'gRPC/GRPCClient'
-    ps.dependency 'gRPC/RxLibrary'
-    ps.dependency 'Protobuf', '~> 3.0.0-alpha-3'
+  s.subspec 'ProtoRPC' do |ss|
+    src_dir = "#{objc_dir}/ProtoRPC"
+    ss.source_files = "#{src_dir}/*.{h,m}"
+    ss.header_mappings_dir = "#{objc_dir}"
+
+    ss.dependency 'gRPC/GRPCClient'
+    ss.dependency 'gRPC/RxLibrary'
+    ss.dependency 'Protobuf', '~> 3.0.0-alpha-3'
   end
 end