Really fix spurious build failures and make it more safer. Header file is

generated on the current working directory regardless of -o option.

sysutils/acpica-tools/files/patch-generate_unix_iasl_Makefile

@@ -1,6 +1,6 @@
---- generate/unix/iasl/Makefile.orig	2016-02-12 17:14:36 UTC
+--- generate/unix/iasl/Makefile.orig	2016-03-18 16:25:41 UTC
 +++ generate/unix/iasl/Makefile
-@@ -272,12 +272,11 @@ include ../Makefile.rules
+@@ -274,12 +274,11 @@ include ../Makefile.rules
  # Function to safely execute yacc
  #
  safe_yacc = \
@@ -10,11 +10,11 @@
 -	$(YACC) $(YFLAGS) -p$(1) -o$$_d/$$_f.c -d $(2) &&\
 -	mv $$_d/$$_f.$${_t\#\#*.} $(3);\
 -	test -d $$_d && rm -fr $$_d
-+	_d=$$(mktemp -d $(3).XXXXXX) &&\
-+	_t=$$_d/$(notdir $(basename $(2))) &&\
-+	$(YACC) $(YFLAGS) -p$(1) -o$$_t.c -d $(2) &&\
-+	mv $$_t$(suffix $(3)) $(3) &&\
-+	rm -fr $$_d
++	_d=$$(mktemp -d '$(abspath $(OBJDIR))/$(1).XXXXXX') &&\
++	cd "$$_d" &&\
++	$(YACC) $(YFLAGS) -p$(1) -o$(1).c -d '$(abspath $(2))' &&\
++	mv $(1)$(suffix $(3)) '$(abspath $(3))' &&\
++	rm -fr "$$_d"
  
  #
  # Macro processing for iASL .y files