Fix unix/Makefile to build on OSX

[blmorris]

Please comment and review - I am not an expert in the subtleties of Makefiles!

This unix/Makefile change should allow the unix port to build on OSX without breaking stmhal build on OSX or affecting other platforms. Tested build for unix and stmhal on OSX 10.7.5 (Lion):

Force OSX to compile with clang even if gcc is available
Change LDFLAGS syntax to be compatible with clang
Fix questionable syntax on line 90
Remove extraneous tab character on line 102

[blmorris]

Sounds good, I'll be able to update the PR later this evening.

[blmorris]

Actually, your suggestion will change the syntax suggested in #782 (comment) to have clang make the map file.
And I'm also not sure if line 90 should be LDFLAGS or LDFLAGS_MOD

[blmorris]

I see what to do now.
Line 32 will be

LDFLAGS = $(LDFLAGS_MOD) -lm -Wl(LDFLAGS_MAP_EXTRA) $(LDFLAGS_EXTRA)

Then LDFLAGS_MAP_EXTRA will be ,-map,$@.map or ,-Map=$@.map$,--cref

Edited to add: That seems to work. Any thoughts on line 90 being LDFLAGS or LDFLAGS_MOD?
Seems to compile fine either way.

[dhylands]

@blmorris Ahh - I missed the -M -m difference. In that case, I would just call it LDFLAGS_MAP and make it equal to -Wl,-map,$@.map or -Wl,-Map=$@.map,--cref

Then you have the option of setting LDFLAGS_MAP to the empty string to not get a map file at all.

[dpgeorge]

Couldn't the order and map stuff be put in the same variable. Eg:

ifeq ($(UNAME_S),Darwin)
# Force OSX to use clang even if gcc is present, value set in mkenv.mk
# must be ovewritten here to avoid breaking stmhal build on OSX
CC = clang
# Use clang syntax for LDFLAGS
LDFLAGS_ARCH = -Wl,-order_file,$(BUILD)/order.def -Wl,-map=$@.map
else
LDFLAGS_ARCH = -Wl,-Map=$@.map,--cref
endif
LDFLAGS = $(LDFLAGS_ARCH) -lm $(LDFLAGS_EXTRA)

Of course, then you can't easily override to get no map file.

[blmorris]

Doesn't LDFLAGS_MOD need to be somewhere in the definition? There are several lines later in the file that manipulate the value of LDFLAGS_MOD, and without a placeholder in LDFLAGS it seems that all of those values simply get skipped over.
As for skipping map file creation, as far as I can tell clang makes the map file without any problems as long as it is given the right syntax, (which is what we are trying to do here), so is there any compelling reason to leave an option to skip it?

[dpgeorge]

Yes, you are right, LDFLAGS_MOD should be in there:

LDFLAGS = $(LDFLAGS_MOD) $(LDFLAGS_ARCH) -lm $(LDFLAGS_EXTRA)

[blmorris]

Got it. I'll test that on my system and update the PR if it works out.

[blmorris]

I just realized that LDFLAGS_EXTRA is not used anywhere else in unix/Makefile; am I correct that this is just a placeholder for flags to be added later in the build process?

[dpgeorge]

am I correct that this is just a placeholder for flags to be added later in the build process?

Yes, it's used if you want to add options from the command line.

[blmorris]

Both unix and stmhal build on my system, and it checks out on Travis too. Anything else we might have missed?
Actually Travis is still working...

[dpgeorge]

Thank you!