This macro searches for a GNU version of make. If a match is found, the makefile variable ‘ifGNUmake’ is set to the empty string, otherwise it is set to "#". This is useful for including a special features in a Makefile, which cannot be handled by other versions of make. The variable _cv_gnu_make_command is set to the command to invoke GNU make if it exists, the empty string otherwise.
Here is an example of its use:
Makefile.in might contain:
# A failsafe way of putting a dependency rule into a makefile $(DEPEND): $(CC) -MM $(srcdir)/*.c > $(DEPEND)
@ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND))) @ifGNUmake@ include $(DEPEND) @ifGNUmake@ endif
Then configure.in would normally contain:
Then perhaps to cause gnu make to override any other make, we could do something like this (note that GNU make always looks for GNUmakefile first):
if ! test x$_cv_gnu_make_command = x ; then mv Makefile GNUmakefile echo .DEFAULT: > Makefile ; echo \ $_cv_gnu_make_command \$@ >> Makefile; fi
Then, if any (well almost any) other make is called, and GNU make also exists, then the other make wraps the GNU make.
Download the latest version of ax_check_gnu_make.m4 or browse the macro’s revision history.
Copyright © 2008 John Darrington email@example.com
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