CMake: Fix CMAKE_CONFIGURATION_TYPES not including Coverage

Coverage is added based on the value of CMAKE_CXX_COMPILER_ID, which isn't known until after the project() call.

This fixes a regression in f26f7d22260b85ea4d0d6044dc2c410ad1da8a20

CMakeLists.txt

@@ -32,24 +32,16 @@ a CMake < 3.9. Making a guess if this is a multi-config generator.")
   endif()
 endif()
 
-# Define the type of build we are setting up.
-set(_configs Standard Release RelWithDebInfo Debug MinSizeRel)
-if(CMAKE_CXX_COMPILER_ID MATCHES "(AppleClang|Clang|GCC)")
-  list(APPEND _configs Coverage)
-endif()
-
+# Set the default CMAKE_BUILD_TYPE before calling project().
 if(IS_MULTICONFIG)
   message(STATUS "Using multi-configuration generator")
-  set(CMAKE_CONFIGURATION_TYPES "${_configs}" CACHE STRING "")
 else()
-  # Set the default CMAKE_BUILD_TYPE before calling project().
   if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Standard CACHE STRING "Choose the type of build." FORCE)
     message(STATUS "Using default build type ${CMAKE_BUILD_TYPE}")
   else()
     message(STATUS "Using build type ${CMAKE_BUILD_TYPE}")
   endif()
-  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS ${_configs})
 endif()
 
 # Set defaults for macOS, must be before project().
@@ -76,6 +68,20 @@ project(Panda3D VERSION ${_version})
 unset(_version)
 unset(_s)
 
+# Determine the possible build types.  Must be *after* calling project().
+set(_configs Standard Release RelWithDebInfo Debug MinSizeRel)
+if(CMAKE_CXX_COMPILER_ID MATCHES "(AppleClang|Clang|GCC)")
+  list(APPEND _configs Coverage)
+endif()
+
+message("available configs are ${_configs}")
+
+if(IS_MULTICONFIG)
+  set(CMAKE_CONFIGURATION_TYPES "${_configs}" CACHE STRING "" FORCE)
+else()
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS ${_configs})
+endif()
+
 enable_testing()
 
 string(REPLACE "$(EFFECTIVE_PLATFORM_NAME)" "" PANDA_CFG_INTDIR "${CMAKE_CFG_INTDIR}")