02/64: Add a function for looking up programs in $PATH

[Ludovic Courtès]

civodul pushed a commit to branch nix
in repository guix.

commit 581a160c11dd3de66d9cd1a6e01c0641909546ef
Author: Eelco Dolstra <address@hidden>
Date:   Fri Feb 14 20:12:04 2014 +0100

    Add a function for looking up programs in $PATH
---
 functions.mk |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/functions.mk b/functions.mk
index 51f6457..1287e43 100644
--- a/functions.mk
+++ b/functions.mk
@@ -5,3 +5,7 @@ rwildcard=$(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2) 
$(filter $(subst
 # Given a file name, produce the corresponding dependency file
 # (e.g. ‘foo/bar.o’ becomes ‘foo/.bar.o.dep’).
 filename-to-dep = $(dir $1).$(notdir $1).dep
+
+# Return the full path to a program by looking it up in $PATH, or the
+# empty string if not found.
+find-program = $(shell for i in $$(IFS=: ; echo $$PATH); do p=$$i/$(strip $1); 
if [ -e $$p ]; then echo $$p; break; fi; done)