Problem: Draft build not enabled for git cloned cppzmq.

When cppzmq is build out of source e.g. ${CMAKE_SOURCE_DIR}/build:

mkdir build
cd build
cmake ..

then .git is not found properly, DRAFT build not enabled and poller test
not added to pool of tests.

Author: kurdybacha

CMakeLists.txt

@@ -19,17 +19,17 @@ if (ZeroMQ_FOUND AND (NOT TARGET libzmq OR NOT TARGET libzmq-static))
   message(FATAL_ERROR "ZeroMQ version not supported!")
 endif()
 
-if (EXISTS "${SOURCE_DIR}/.git")
+if (EXISTS "${CMAKE_SOURCE_DIR}/.git")
     OPTION (ENABLE_DRAFTS "Build and install draft classes and methods" ON)
 else ()
     OPTION (ENABLE_DRAFTS "Build and install draft classes and methods" OFF)
 endif ()
-IF (ENABLE_DRAFTS)
+if (ENABLE_DRAFTS)
     ADD_DEFINITIONS (-DZMQ_BUILD_DRAFT_API)
     set (pkg_config_defines "-DZMQ_BUILD_DRAFT_API=1")
-ELSE (ENABLE_DRAFTS)
+else (ENABLE_DRAFTS)
     set (pkg_config_defines "")
-ENDIF (ENABLE_DRAFTS)
+endif (ENABLE_DRAFTS)
 
 message(STATUS "cppzmq v${CPPZMQ_VERSION}")