From 43836ced828362e174fd7ac20c2995312abd2f99 Mon Sep 17 00:00:00 2001
From: Jan Tattermusch <jtattermusch@google.com>
Date: Wed, 22 Aug 2018 17:14:54 +0200
Subject: [PATCH] cmake: add backwards compatibility mode

---
 templates/CMakeLists.txt.template | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/templates/CMakeLists.txt.template b/templates/CMakeLists.txt.template
index aec1624acdb..5fff74f128e 100644
--- a/templates/CMakeLists.txt.template
+++ b/templates/CMakeLists.txt.template
@@ -88,6 +88,7 @@
   option(gRPC_BUILD_TESTS "Build tests" OFF)
   option(gRPC_BUILD_CODEGEN "Build codegen" ON)
   option(gRPC_BUILD_CSHARP_EXT "Build C# extensions" ON)
+  option(gRPC_BACKWARDS_COMPATIBILITY_MODE "Build libraries that are binary compatible across a larger number of OS and libc versions" OFF)
 
   set(gRPC_INSTALL_default ON)
   if (NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
@@ -164,6 +165,14 @@
     set(_gRPC_PROTOBUF_LIBRARY_NAME "libprotobuf")
   endif()
 
+  if(gRPC_BACKWARDS_COMPATIBILITY_MODE)
+    add_definitions(-DGPR_BACKWARDS_COMPATIBILITY_MODE)
+    if (_gRPC_PLATFORM_MAC)
+      # CMAKE_OSX_DEPLOYMENT_TARGET
+      add_definitions(-mmacosx-version-min=10.7)
+    endif()
+  endif()
+
   if (_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC)
     # C core has C++ source code, but should not depend on libstc++ (for better portability).
     # We need to use a few tricks to convince cmake to do that.