How to create a directory in a makefile when mkdir -p is not available? - gnu-make

Question

I have a makefile which does the usual directory creation:
$(Release_target_OBJDIR)/%.o: %.cpp
mkdir -p $(dir $#)
$(COMPILE.cpp) $< $(CFLAGS) $(INCLUDES) -o $#
Unfortunately when I run this under scratchbox2 the mkdir -p command always fails silently.
I attempted the following kludge which doesn't work:
$(Release_target_OBJDIR)/%.o: %.cpp
mkdir $(dir $(dir $(dir $#)))
mkdir $(dir $(dir $#))
mkdir $(dir $#)
$(COMPILE.cpp) $< $(CFLAGS) $(INCLUDES) -o $#
This outputs:
mkdir -p /home/foo/projects/htc/arm/obj/cbar/release/
mkdir -p /home/foo/projects/htc/arm/obj/cbar/release/
mkdir -p /home/foo/projects/htc/arm/obj/cbar/release/
... the trailing slash prevents the dir function from stripping the last directory in the way I wanted.
Short of writing a script or small C app to replicate the "-p" functionality, does anyone have any ideas for creating the subdirectories within the makefile?
Without the -p option mkdir will give an error when the makefile tries to create a directory which already exists. I can do mkdir blah 2> /dev/null but then I risk losing other error messages.
Does anyone have any thoughts as to why mkdir -p doesn't work under scratchbox2?
EDIT
Based on suggestions by bobbogo I put this together. It looks fairly convoluted, but seems to work, even under scratchbox2.
# Generic variables for use in functions
comma:= ,
empty:=
space:= $(empty) $(empty)
# Make directory function
forlooprange = $(wordlist 1,$(words $1),1 2 3 4 5 6 7 8 9 10)
forloop = $(foreach n,$(call forlooprange,$1),$(call $2,$n,$3))
mkdirfunc0 = test -d $1 || mkdir $1;
mkdirfunc1 = $(call mkdirfunc0,/$(subst $(space),/,$(foreach n,$(wordlist 1,$1,$2),$n)))
mkdirfunc2 = $(call forloop,$1,mkdirfunc1,$1)
mkdirmain = $(call mkdirfunc2,$(subst /, ,$1))
.PRECIOUS: %/.sentinel
%/.sentinel:
$(call mkdirmain,$*)
touch $#

Answer 1

You can replace your forest of mkdirs with this:
$(Release_target_OBJDIR)/%.o: %.cpp
$(foreach d,$(subst /, ,${#D}),mkdir $d && cd $d && ):
∶
This will create a shell command somethng like this:
mkdir projects && cd projects && mkdir htc && cd htc && mkdir arm && cd arm && :
This runs for every compile. Not very elegant. You could optimise this by using some sort of sentinel file. For instance:
$(Release_target_OBJDIR)/%.o: %.cpp ${Release_target_OBJDIR}/.sentinel
∶
%/.sentinel:
$(foreach d,$(subst /, ,$*),mkdir $d && cd $d && ):
touch $#
.sentinel gets created once before all objects, and is make -j friendly. In fact you should do it this way even if mkdir -p works for you (in which case you would use mkdir -p rather than the $(foreach) hacksolution).

Answer 2

You can tell make to ignore any failure return code from a command using -:
$(Release_target_OBJDIR)/%.o: %.cpp
-mkdir $(dir $(dir $(dir $#)))
-mkdir $(dir $(dir $#))
-mkdir $(dir $#)
$(COMPILE.cpp) $< $(CFLAGS) $(INCLUDES) -o $#
(Note that this doesn't address the trailing slash problem.)