0002-Disable-physics-for-MPAS-dycore-only-build.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kuan-Chih Wang <kuanchihw@ucar.edu>
Date: Thu, 1 Aug 2024 17:09:58 -0600
Subject: [PATCH] Disable physics for MPAS dycore-only build

When building MPAS as a dycore, all physics-related components are disabled.
This build configuration is usually used by CAM/CAM-SIMA, and can be achieved by
defining the `MPAS_CAM_DYCORE` macro in `CPPFLAGS`.

The `PHYSICS` variable controls whether physics are enabled in MPAS, but its logic
is decoupled from the `MPAS_CAM_DYCORE` macro. Disabling physics in MPAS currently
requires manual interventions.

Therefore, automatically disable physics when the `MPAS_CAM_DYCORE` macro is found
in `CPPFLAGS`.

This downstream patch is maintained by CAM-SIMA for its particular use case of MPAS.
---
 src/core_atmosphere/Makefile | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/core_atmosphere/Makefile b/src/core_atmosphere/Makefile
index 8d9f4f1a..cac8255e 100644
--- a/src/core_atmosphere/Makefile
+++ b/src/core_atmosphere/Makefile
@@ -4,8 +4,11 @@
 # To build a dycore-only MPAS-Atmosphere model, comment-out or delete
 # the definition of PHYSICS, below
 #
-PHYSICS=-DDO_PHYSICS
-
+# If MPAS_CAM_DYCORE is found in CPPFLAGS, PHYSICS will become undefined automatically
+#
+ifeq ($(findstring MPAS_CAM_DYCORE,$(CPPFLAGS)),)
+    PHYSICS = -DDO_PHYSICS
+endif
 
 ifdef PHYSICS
     PHYSCORE = physcore
-- 
2.43.0