Make CMAKE_BUILD_TYPE default as release

#34

Change-Id: Ib1a95807f516e3675cb1a4aab7b2433e87f0b325

Author: iwwu

IGC/CMakeLists.txt

@@ -1904,11 +1904,11 @@ else()
     elseif(_buildType MATCHES "^debug$")
       set(_buildType "Debug")
     else()
-      set(_buildType "Debug")
+      set(_buildType "Release")
       message(WARNING "CMAKE_BUILD_TYPE: Unknown build configuration. The following configurations are available: ${IGC_CMAKE_CONFIGURATION_TYPES}.\nThe \"${_buildType}\" configuration will be used.\nThis value has meaning only for single-configuration generators (like Make). It will be ignored for MSVC/XCode.")
     endif()
   else()
-    set(_buildType "Debug")
+    set(_buildType "Release")
     message(WARNING "CMAKE_BUILD_TYPE: No build configuration specified. The following configurations are available: ${IGC_CMAKE_CONFIGURATION_TYPES}.\nThe \"${_buildType}\" configuration will be used.\nThis value has meaning only for single-configuration generators (like Make). It will be ignored for MSVC/XCode.")
   endif()
   set(CMAKE_BUILD_TYPE "${_buildType}")