cmake: add Find<package>.cmake find module method for thrift (#1020)

CMakeLists.txt

@@ -15,6 +15,8 @@ project(opentelemetry-cpp)
 # Mark variables as used so cmake doesn't complain about them
 mark_as_advanced(CMAKE_TOOLCHAIN_FILE)
 
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules/")
+
 if(DEFINED ENV{ARCH})
   # Architecture may be specified via ARCH environment variable
   set(ARCH $ENV{ARCH})
@@ -223,7 +225,7 @@ function(install_windows_deps)
 endfunction()
 
 if(WITH_JAEGER)
-  find_package(Thrift QUIET CONFIG)
+  find_package(Thrift QUIET)
   if(NOT Thrift_FOUND)
     # Install Thrift and propagate via vcpkg toolchain file
     if(WIN32 AND (NOT DEFINED CMAKE_TOOLCHAIN_FILE))

cmake/modules/FindThrift.cmake

@@ -0,0 +1,31 @@
+# This module defines Thrift_LIBRARIES, libraries to link Thrift_INCLUDE_DIR,
+# Thrift_FOUND, If false, do not try to use it.
+
+# prefer the Thrift version supplied in Thrift_HOME (cmake -DThrift_HOME then
+# environment)
+find_path(
+  Thrift_INCLUDE_DIR
+  NAMES thrift/Thrift.h
+  HINTS ${Thrift_HOME} ENV Thrift_HOME /usr/local /opt/local
+  PATH_SUFFIXES include)
+
+# prefer the Thrift version supplied in Thrift_HOME
+find_library(
+  Thrift_LIBRARIES
+  NAMES thrift libthrift
+  HINTS ${Thrift_HOME} ENV Thrift_HOME /usr/local /opt/local
+  PATH_SUFFIXES lib lib64)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Thrift DEFAULT_MSG Thrift_LIBRARIES
+                                  Thrift_INCLUDE_DIR)
+mark_as_advanced(Thrift_LIBRARIES Thrift_INCLUDE_DIR)
+
+
+if(Thrift_FOUND AND NOT (TARGET thrift::thrift))
+  add_library(thrift::thrift UNKNOWN IMPORTED)
+  set_target_properties(
+    thrift::thrift
+    PROPERTIES IMPORTED_LOCATION ${Thrift_LIBRARIES}
+	       INTERFACE_INCLUDE_DIRECTORIES ${Thrift_INCLUDE_DIR})
+endif()