Add gnu stuff for completeness

Exec/DevTests/MiguelDev/GNUmakefile

@@ -0,0 +1,37 @@
+# AMReX
+COMP = gnu
+PRECISION = DOUBLE
+
+# Profiling
+PROFILE       = FALSE
+TINY_PROFILE  = TRUE
+COMM_PROFILE  = FALSE
+TRACE_PROFILE = FALSE
+MEM_PROFILE   = FALSE
+USE_GPROF     = FALSE
+
+# Performance
+USE_MPI  = TRUE
+USE_OMP  = FALSE
+
+USE_CUDA = FALSE
+USE_HIP  = FALSE
+USE_SYCL = FALSE
+
+# Physics
+USE_MOISTURE = FALSE
+
+# Debugging
+DEBUG = FALSE
+
+TEST = TRUE
+USE_ASSERTION = TRUE
+
+#USE_POISSON_SOLVE = TRUE
+
+# GNU Make
+Bpack := ./Make.package
+Blocs := .
+ERF_HOME := ../..
+ERF_PROBLEM_DIR = $(ERF_HOME)/Exec/DevTests/MiguelDev
+include $(ERF_HOME)/Exec/Make.ERF

Exec/DevTests/MiguelDev/Make.package

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+CEXE_headers += prob.H
+CEXE_sources += prob.cpp