Update makefiles after MachineArithmetic moved packages to src dire…

…ctory

MachineArithmetic commit 2eab9386 "Move smalltalk sources to `src` directory"
moved all packages into `src` subdirectory. This commit updates makefiles
to reflect this change.

pharo/GNUmakefile

@@ -32,7 +32,7 @@ build: prereq $(PROJECT).image
 
 $(PROJECT).image: ../src/*/*.st
 	$(call pharo-copy-image, $(PHARO_IMAGE), $@)
-	$(call pharo-load-local, $@, MachineArithmetic,$(MACHINEARITHMETIC_DIR))
+	$(call pharo-load-local, $@, MachineArithmetic,$(MACHINEARITHMETIC_DIR)/src)
 	$(call pharo-load-local, $@, ArchC,            ../src)
 
 run: build

stx/GNUmakefile

@@ -33,13 +33,13 @@ build: prereq
 run: build
 	ARCHC_PDL_DIR=$(ARCHC_PDL_DIR)/ $(STX) \
 		--quick \
-		--package-path $(MACHINEARITHMETIC_DIR) \
+		--package-path $(MACHINEARITHMETIC_DIR)/src \
 		--package-path ../src \
 		--load BaselineOf$(PROJECT) \
 
 test: build
 	ARCHC_PDL_DIR=$(ARCHC_PDL_DIR)/ $(STX) \
-		--package-path $(MACHINEARITHMETIC_DIR) \
+		--package-path $(MACHINEARITHMETIC_DIR)/src \
 		--package-path ../src \
 		--load BaselineOf$(PROJECT) \
 		--run Builder::ReportRunner -r Builder::TestReport --fail-on-failure \