building gen-scmconfig.c on FreeBSD

[Andreas Vögele]

On FreeBSD string.h includes the system header strings.h.  The problem 
is that Guile provides another file called strings.h which is included 
instead of the system header file. This causes the build of 
gen-scmconfig to fail since Guile's strings.h includes scmconfig.h 
which hasn't been created at this stage.

It seems that there is already a workaround for this problem in 
linguile/Makefile.am:

 ## Prevent automake from adding extra -I options
 DEFS = @DEFS@

Unfortunately, that workaround no longer helps since recent versions of 
automake seem to work differently.  I tried to use "DEFS = @DEFS@ 
-I/usr/include" so that /usr/include is searched before the 
DEFAULT_INCLUDES. But that didn't work since GCC seems to search the 
current directory before the directories added with -I. I also tried to 
use -I- without success.

I figured out that gen-scmconfig can be built with CC_FOR_BUILD instead 
of COMPILE.  I'm wondering if the rule

gen-scmconfig.$(OBJEXT): gen-scmconfig.c
        if [ "$(cross_compiling)" = "yes" ]; then \
                $(CC_FOR_BUILD) $(DEFS) $(INCLUDES) -c -o $@ $<; \
        else \
                $(COMPILE) -c -o $@ $<; \
        fi

in libguile/Makefile.am couldn't be replaced with

gen-scmconfig.$(OBJEXT): gen-scmconfig.c
        $(CC_FOR_BUILD) $(DEFS) $(INCLUDES) -c -o $@ $<;

Does anybody know a better solution?