Merge branch 'js/maint-no-ln-across-libexec-and-bin' into maint

* js/maint-no-ln-across-libexec-and-bin:
  Add NO_CROSS_DIRECTORY_HARDLINKS support to the Makefile

Conflicts:
	Makefile

Author: gitster

Makefile

@@ -175,6 +175,9 @@ all::
 # Define OBJECT_CREATION_USES_RENAMES if your operating systems has problems
 # when hardlinking a file to another name and unlinking the original file right
 # away (some NTFS drivers seem to zero the contents in that scenario).
+#
+# Define NO_CROSS_DIRECTORY_HARDLINKS if you plan to distribute the installed
+# programs as a tar, where bin/ and libexec/ might be on different file systems.
 
 GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1550,6 +1553,7 @@ endif
 	bindir=$$(cd '$(DESTDIR_SQ)$(bindir_SQ)' && pwd) && \
 	execdir=$$(cd '$(DESTDIR_SQ)$(gitexec_instdir_SQ)' && pwd) && \
 	{ $(RM) "$$execdir/git-add$X" && \
+		test -z "$(NO_CROSS_DIRECTORY_HARDLINKS)" && \
 		ln "$$bindir/git$X" "$$execdir/git-add$X" 2>/dev/null || \
 		cp "$$bindir/git$X" "$$execdir/git-add$X"; } && \
 	{ for p in $(filter-out git-add$X,$(BUILT_INS)); do \