[PATCH] build: don't prefix the RHS of "GPERF = ..." with "lib/"

[Jim Meyering]

I built from scratch in a just-cloned directory and hit this failure:

    $ make V=1 -j1
    lib/gperf -m 10 ./lib/iconv_open-aix.gperf > ./lib/iconv_open-aix.h-t
    /bin/sh: lib/gperf: No such file or directory
    make: *** [lib/iconv_open-aix.h] Error 127
    [Exit 2]

That is because our kludgy new prefix-gnulib-mk script made this
silly change to lib/gnulib.mk:

    - GPERF = gperf
    + GPERF = lib/gperf

One would notice that only when building from scratch or after
modifying one of the dependents of lib/iconv_open-aix.h.
Not likely.

Here's the probable fix:

>From f6a83d0a9e0e4d87f5e2db91d0efd717f132dbd2 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Fri, 14 Sep 2012 18:19:39 +0200
Subject: [PATCH] build: don't prefix the RHS of "GPERF = ..." with "lib/"

* gl/build-aux/prefix-gnulib-mk (prefix_assignment): Exempt
the RHS of a "GPERF = ..." assignment from lib/ prefixing.
---
 gl/build-aux/prefix-gnulib-mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gl/build-aux/prefix-gnulib-mk b/gl/build-aux/prefix-gnulib-mk
index 38471a9..87debe6 100755
--- a/gl/build-aux/prefix-gnulib-mk
+++ b/gl/build-aux/prefix-gnulib-mk
@@ -108,6 +108,10 @@ sub prefix_assignment ($$)
       # Elide any SUFFIXES assignment or concatenation.
       $lhs_and_assign_op =~ s/^/# /;
     }
+  elsif ($lhs_and_assign_op =~ /^GPERF = /)
+    {
+      # Do not change the RHS, which specifies the GPERF program.
+    }
   # The words are (probably) paths to files in lib/: prefix them.
   else
     {
--
1.7.12.363.g53284de