Fix out of tree clean

Makefile

@@ -95,14 +95,14 @@ TARGETS = $(PROGRAM_PREFIX)yosys$(EXE) $(PROGRAM_PREFIX)yosys-config
 PRETTY = 1
 SMALL = 0
 
-# Unit test
-UNITESTPATH := tests/unit
-
 all: top-all
 
 YOSYS_SRC := $(dir $(firstword $(MAKEFILE_LIST)))
 VPATH := $(YOSYS_SRC)
 
+# Unit test
+UNITESTPATH := $(YOSYS_SRC)/tests/unit
+
 export CXXSTD ?= c++17
 CXXFLAGS := $(CXXFLAGS) -Wall -Wextra -ggdb -I. -I"$(YOSYS_SRC)" -MD -MP -D_YOSYS_ -fPIC -I$(PREFIX)/include
 LIBS := $(LIBS) -lstdc++ -lm
@@ -1150,7 +1150,7 @@ clean: clean-py clean-unit-test
 	rm -f tests/svinterfaces/*.log_stdout tests/svinterfaces/*.log_stderr tests/svinterfaces/dut_result.txt tests/svinterfaces/reference_result.txt tests/svinterfaces/a.out tests/svinterfaces/*_syn.v tests/svinterfaces/*.diff
 	rm -f  tests/tools/cmp_tbdata
 	rm -f $(addsuffix /run-test.mk,$(MK_TEST_DIRS))
-	-$(MAKE) -C docs clean
+	-$(MAKE) -C $(YOSYS_SRC)/docs clean
 	rm -rf docs/util/__pycache__
 	rm -f libyosys.so
 
@@ -1162,7 +1162,7 @@ clean-py:
 	rm -rf kernel/*.pyh
 
 clean-abc:
-	$(MAKE) -C abc DEP= clean
+	$(MAKE) -C $(YOSYS_SRC)/abc DEP= clean
 	rm -f $(PROGRAM_PREFIX)yosys-abc$(EXE) $(PROGRAM_PREFIX)yosys-libabc.a abc/abc-[0-9a-f]* abc/libabc-[0-9a-f]*.a .git-abc-submodule-hash
 
 mrproper: clean