[Bioc-devel] portable make syntax

[Laurent Gatto]

Dear all,

I have been using the following in various vignettes/Makefile

ifeq (${R_HOME},)
R_HOME= $(shell R RHOME)
endif

This syntax is GNU specific and now results in warnings when checking
the package:

* checking for GNU extensions in Makefiles ... WARNING
Found the following file(s) containing GNU extensions:
  vignettes/Makefile
Portable Makefiles do not use GNU extensions such as +=, :=, $(shell),
$(wildcard), ifeq ... endif. See section ‘Writing portable packages’ in
the ‘Writing R Extensions’ manual.

I couldn't find anything in R-exts; does anyone know a more portable
syntax?

Alternatively, I could add

SystemRequirements: GNU make

to my DESCRIPTION file, which however does not seem ideal.

Any suggestions?

Thank you very much in advance.

Laurent