[PATCH v3 1/1] perl: fix installing modules from contrib

[Christian Hesse <mail@eworm.de>]

Commit 20d2a30f (Makefile: replace perl/Makefile.PL with simple make rules)
removed a target that allowed Makefiles from contrib/ to get the correct
install path. This introduces a new target for main Makefile and fixes
installation for Mediawiki module.

v2: Pass prefix as that can have influence as well, add single quotes
    for _SQ variant.
v3: Rename target, add to .PHONY.

Signed-off-by: Christian Hesse <mail@eworm.de>
---
 Makefile                   | 3 +++
 contrib/mw-to-git/Makefile | 5 +++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index f18168725..5a06eddf2 100644
--- a/Makefile
+++ b/Makefile
@@ -2014,6 +2014,9 @@ GIT-PERL-DEFINES: FORCE
 		echo "$$FLAGS" >$@; \
 	    fi
 
+.PHONY: say-perllibdir
+say-perllibdir:
+	@echo '$(perllibdir_SQ)'
 
 .PHONY: gitweb
 gitweb:
diff --git a/contrib/mw-to-git/Makefile b/contrib/mw-to-git/Makefile
index a4b6f7a2c..e301a5b4e 100644
--- a/contrib/mw-to-git/Makefile
+++ b/contrib/mw-to-git/Makefile
@@ -21,8 +21,9 @@ HERE=contrib/mw-to-git/
 INSTALL = install
 
 SCRIPT_PERL_FULL=$(patsubst %,$(HERE)/%,$(SCRIPT_PERL))
-INSTLIBDIR=$(shell $(MAKE) -C $(GIT_ROOT_DIR)/perl \
-                -s --no-print-directory instlibdir)
+INSTLIBDIR=$(shell $(MAKE) -C $(GIT_ROOT_DIR)/ \
+                -s --no-print-directory prefix=$(prefix) \
+                perllibdir=$(perllibdir) say-perllibdir)
 DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
 INSTLIBDIR_SQ = $(subst ','\'',$(INSTLIBDIR))