Add GNU_CRAY_LDFLAGS flag to MPAS standalone builds

This should be set to:
```
export GNU_CRAY_LDFLAGS="-Wl,--enable-new-dtags"
```
on Chicoma-CPU with gcc.

components/mpas-framework/Makefile

@@ -396,11 +396,11 @@ gnu-cray:
 	"FFLAGS_OPT = -O3 -m64 -ffree-line-length-none -fconvert=big-endian -ffree-form -ffpe-summary=none $${EXTRA_FFLAGS}" \
 	"CFLAGS_OPT = -O3 -m64" \
 	"CXXFLAGS_OPT = -O3 -m64" \
-	"LDFLAGS_OPT = -O3 -m64" \
+	"LDFLAGS_OPT = -O3 -m64 $(GNU_CRAY_LDFLAGS)" \
 	"FFLAGS_DEBUG = -g -m64 -ffree-line-length-none -fconvert=big-endian -ffree-form -fbounds-check -fbacktrace -ffpe-trap=invalid,zero,overflow -ffpe-summary=none $${EXTRA_FFLAGS}" \
 	"CFLAGS_DEBUG = -g -m64" \
 	"CXXFLAGS_DEBUG = -g -m64" \
-	"LDFLAGS_DEBUG = -g -m64" \
+	"LDFLAGS_DEBUG = -g -m64 $(GNU_CRAY_LDFLAGS)" \
 	"FFLAGS_OMP = -fopenmp" \
 	"CFLAGS_OMP = -fopenmp" \
 	"BUILD_TARGET = $(@)" \