From 4ebb978d98881832ae2e2c56793b6abb2291df90 Mon Sep 17 00:00:00 2001
From: Gustavo Lopes <mail@geleia.net>
Date: Wed, 30 Nov 2022 12:51:01 +0000
Subject: [PATCH] Fix build on Mac OS/libc++; allow setting build type

---
 CMakeLists.txt      | 16 ++++++++++++++--
 src/datadog/clock.h |  5 +++--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 13f2b15a..34d40994 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,7 +7,9 @@ project(dd-trace-cpp)
 option(BUILD_COVERAGE "Build code with code coverage profiling instrumentation" OFF)
 option(BUILD_EXAMPLE "Build the example program (example/)" OFF)
 
-set(CMAKE_BUILD_TYPE "RelWithDebInfo")
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE RelWithDebInfo)
+endif()
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 set(CMAKE_CXX_STANDARD 17)
@@ -30,6 +32,13 @@ ExternalProject_Add(curl
   INSTALL_COMMAND make install
 )
 
+add_library(libcurl INTERFACE IMPORTED GLOBAL)
+target_include_directories(libcurl INTERFACE ${CMAKE_BINARY_DIR}/include)
+
+execute_process(COMMAND ${CMAKE_BINARY_DIR}/bin/curl-config --static-libs
+  OUTPUT_VARIABLE CURL_LINK_OPTS OUTPUT_STRIP_TRAILING_WHITESPACE)
+target_link_options(libcurl INTERFACE "SHELL:${CURL_LINK_OPTS}")
+
 if (MSVC)
     add_compile_options(/W4 /WX)
 else()
@@ -163,12 +172,15 @@ target_include_directories(dd_trace_cpp PRIVATE ${CMAKE_BINARY_DIR}/include)
 
 # Linking this library requires libcurl and threads.
 find_package(Threads REQUIRED)
-target_link_libraries(dd_trace_cpp PRIVATE ${CMAKE_BINARY_DIR}/lib/libcurl.a PUBLIC Threads::Threads ${COVERAGE_LIBRARIES})
+target_link_libraries(dd_trace_cpp PRIVATE libcurl Threads::Threads ${COVERAGE_LIBRARIES})
 
 # When installing, install the library and its public headers.
 
 install(TARGETS dd_trace_cpp
+  EXPORT dd_trace_cpp-config
   FILE_SET public_headers)
+install(EXPORT dd_trace_cpp-config
+  DESTINATION share/cmake/dd_trace_cpp)
 
 if(BUILD_TESTING)
   add_subdirectory(test)
diff --git a/src/datadog/clock.h b/src/datadog/clock.h
index a2758a47..4385475c 100644
--- a/src/datadog/clock.h
+++ b/src/datadog/clock.h
@@ -26,6 +26,7 @@ namespace datadog {
 namespace tracing {
 
 using Duration = std::chrono::steady_clock::duration;
+using SystemDuration = std::chrono::system_clock::duration;
 
 struct TimePoint {
   std::chrono::system_clock::time_point wall =
@@ -39,11 +40,11 @@ inline Duration operator-(const TimePoint& after, const TimePoint& before) {
 }
 
 inline TimePoint operator-(const TimePoint& origin, Duration offset) {
-  return {origin.wall - offset, origin.tick - offset};
+  return {origin.wall - std::chrono::duration_cast<SystemDuration>(offset), origin.tick - offset};
 }
 
 inline TimePoint& operator+=(TimePoint& self, Duration offset) {
-  self.wall += offset;
+  self.wall += std::chrono::duration_cast<SystemDuration>(offset);
   self.tick += offset;
   return self;
 }