[PATCH v3 2/4] Makefile: add support for "perllibdir"

[Dan Jacques <dnj@google.com>]

Add the "perllibdir" Makefile variable, which allows the customization
of the Perl library installation path.

The Perl library installation path is currently left entirely to the
Perl Makefile implementation, either MakeMaker (default) or a fixed path
when NO_PERL_MAKEMAKER is enabled. This patch introduces "perllibdir", a
Makefile variable that can override that Perl module installation path.

As with some other Makefile variables, "perllibdir" may be either
absolute or relative. In the latter case, it is treated as relative to
"$(prefix)".

Add some incidental documentation to perl/Makefile.

Explicitly specifying an installation path is necessary for Perl runtime
prefix support, as runtime prefix resolution code must know in advance
where the Perl support modules are installed.

Signed-off-by: Dan Jacques <dnj@google.com>
---
 Makefile      | 18 +++++++++++++-----
 perl/Makefile | 52 ++++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index 5ad60a54c..7a2ed8857 100644
--- a/Makefile
+++ b/Makefile
@@ -462,6 +462,7 @@ ARFLAGS = rcs
 #   mandir
 #   infodir
 #   htmldir
+#   perllibdir
 # This can help installing the suite in a relocatable way.
 
 prefix = $(HOME)
@@ -1721,6 +1722,7 @@ gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 template_dir_SQ = $(subst ','\'',$(template_dir))
 htmldir_relative_SQ = $(subst ','\'',$(htmldir_relative))
 prefix_SQ = $(subst ','\'',$(prefix))
+perllibdir_SQ = $(subst ','\'',$(perllibdir))
 gitwebdir_SQ = $(subst ','\'',$(gitwebdir))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
@@ -1955,17 +1957,22 @@ $(SCRIPT_PERL_GEN): perl/perl.mak
 
 perl/perl.mak: perl/PM.stamp
 
-perl/PM.stamp: FORCE
+perl/PM.stamp: GIT-PERL-DEFINES FORCE
 	@$(FIND) perl -type f -name '*.pm' | sort >$@+ && \
+	cat GIT-PERL-DEFINES >>$@+ && \
 	$(PERL_PATH) -V >>$@+ && \
 	{ cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@; } && \
 	$(RM) $@+
 
-perl/perl.mak: GIT-CFLAGS GIT-PREFIX perl/Makefile perl/Makefile.PL
-	$(QUIET_SUBDIR0)perl $(QUIET_SUBDIR1) PERL_PATH='$(PERL_PATH_SQ)' prefix='$(prefix_SQ)' $(@F)
-
 PERL_HEADER_TEMPLATE = perl/header_fixed_prefix.pl.template
-PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ)
+
+PERL_DEFINES := $(PERL_PATH_SQ) $(PERLLIB_EXTRA_SQ)
+PERL_DEFINES += $(NO_PERL_MAKEMAKER)
+PERL_DEFINES += $(perllibdir)
+
+perl/perl.mak: GIT-CFLAGS GIT-PREFIX perl/Makefile perl/Makefile.PL
+	$(QUIET_SUBDIR0)perl $(QUIET_SUBDIR1) PERL_PATH='$(PERL_PATH_SQ)' \
+	  prefix='$(prefix_SQ)' perllibdir='$(perllibdir_SQ)' $(@F)
 
 $(SCRIPT_PERL_GEN): % : %.perl perl/perl.mak GIT-PERL-DEFINES GIT-PERL-HEADER GIT-VERSION-FILE
 	$(QUIET_GEN)$(RM) $@ $@+ && \
@@ -1979,6 +1986,7 @@ $(SCRIPT_PERL_GEN): % : %.perl perl/perl.mak GIT-PERL-DEFINES GIT-PERL-HEADER GI
 	chmod +x $@+ && \
 	mv $@+ $@
 
+PERL_DEFINES := $(subst $(space),:,$(PERL_DEFINES))
 GIT-PERL-DEFINES: FORCE
 	@FLAGS='$(PERL_DEFINES)'; \
 	    if test x"$$FLAGS" != x"`cat $@ 2>/dev/null`" ; then \
diff --git a/perl/Makefile b/perl/Makefile
index f657de20e..b2aeeb0d8 100644
--- a/perl/Makefile
+++ b/perl/Makefile
@@ -1,6 +1,22 @@
 #
 # Makefile for perl support modules and routine
 #
+# This Makefile generates "perl.mak", which contains the actual build and
+# installation directions.
+#
+# PERL_PATH must be defined to be the path of the Perl interpreter to use.
+#
+# prefix must be defined as the Git installation prefix.
+#
+# localedir must be defined as the path to the locale data.
+#
+# perllibdir may be optionally defined to override the default Perl module
+# installation directory, which is relative to prefix. If perllibdir is not
+# absolute, it will be treated as relative to prefix.
+#
+# NO_PERL_MAKEMAKER may be defined to use a built-in Makefile generation method
+# instead of Perl MakeMaker.
+
 makfile:=perl.mak
 modules =
 
@@ -12,6 +28,16 @@ ifndef V
 	QUIET = @
 endif
 
+# If a library directory is provided, and it is not an absolute path, resolve
+# it relative to prefix.
+ifneq ($(perllibdir),)
+ifneq ($(filter /%,$(firstword $(perllibdir))),)
+perllib_instdir = $(perllibdir)
+else
+perllib_instdir = $(prefix)/$(perllibdir)
+endif
+endif
+
 all install instlibdir: $(makfile)
 	$(QUIET)$(MAKE) -f $(makfile) $@
 
@@ -25,7 +51,12 @@ clean:
 $(makfile): PM.stamp
 
 ifdef NO_PERL_MAKEMAKER
-instdir_SQ = $(subst ','\'',$(prefix)/lib)
+
+ifeq ($(perllib_instdir),)
+perllib_instdir = $(prefix)/lib
+endif
+
+instdir_SQ = $(subst ','\'',$(perllib_instdir))
 
 modules += Git
 modules += Git/I18N
@@ -42,7 +73,7 @@ modules += Git/SVN/Prompt
 modules += Git/SVN/Ra
 modules += Git/SVN/Utils
 
-$(makfile): ../GIT-CFLAGS Makefile
+$(makfile): ../GIT-CFLAGS ../GIT-PERL-DEFINES Makefile
 	echo all: private-Error.pm Git.pm Git/I18N.pm > $@
 	set -e; \
 	for i in $(modules); \
@@ -79,12 +110,21 @@ $(makfile): ../GIT-CFLAGS Makefile
 	echo '	cp private-Error.pm "$$(DESTDIR)$(instdir_SQ)/Error.pm"' >> $@
 	echo instlibdir: >> $@
 	echo '	echo $(instdir_SQ)' >> $@
+
 else
-$(makfile): Makefile.PL ../GIT-CFLAGS
-	$(PERL_PATH) $< PREFIX='$(prefix_SQ)' INSTALL_BASE='' --localedir='$(localedir_SQ)'
+
+# This may be empty if perllibdir was empty.
+instdir_SQ = $(subst ','\'',$(perllib_instdir))
+
+$(makfile): Makefile.PL ../GIT-CFLAGS ../GIT-PERL-DEFINES
+	$(PERL_PATH) $< \
+	  PREFIX='$(prefix_SQ)' INSTALL_BASE='' \
+	  LIB='$(instdir_SQ)' \
+	  --localedir='$(localedir_SQ)'
+
 endif
 
 # this is just added comfort for calling make directly in perl dir
 # (even though GIT-CFLAGS aren't used yet. If ever)
-../GIT-CFLAGS:
-	$(MAKE) -C .. GIT-CFLAGS
+../GIT-CFLAGS ../GIT-PERL-DEFINES:
+	$(MAKE) -C .. $(@F)
-- 
2.15.0.chromium12