bug#44544: Failures Building in non-Git Directory

[Fred Wright]

When running in a directory that's not a git repo, there are at least two 
failures:

MacPro:dejagnu fw$ ./configure
[...]
checking for expect... /usr/bin/expect
checking Tcl version 8.5 or greater... yes
fatal: not a git repository (or any parent up to mount point /Volumes)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
checking that generated files are newer than configure... done
configure: creating ./config.status
config.status: creating Makefile
config.status: executing depfiles commands
MacPro:dejagnu fw$ echo $?
0

Note that the allegedly "fatal" error doesn't avoid a zero exit status 
(which may be a separate bug).

After the "successful" configure, building succeeds, with no error 
messages:

MacPro:dejagnu fw$ make
[...]
        rm -rf $backupdir; exit $rc
Done. Now run 'make install'.
MacPro:dejagnu fw$ echo $?
0

Many tests now fail, which may or may not be related, so that's not 
included here.

But install fails:

MacPro:dejagnu fw$ sudo make install
Password:
Done. Now run 'make install'.
[...]
make  install-data-hook
revision=`cd . &&  git rev-parse --short HEAD` \
	&& sed -i -e "s/^set *frame_version.*/set frame_version 
-${revision}/" /usr/local/share/dejagnu/runtest.exp
fatal: not a git repository (or any parent up to mount point /Volumes)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
make[2]: *** [install-data-hook] Error 128
make[1]: *** [install-data-am] Error 2
make: *** [install-am] Error 2
MacPro:dejagnu fw$ echo $?
2

This is commonly seen when copying all tracked files to another location 
for testing (e.g., using git ls-files and rsync), but for purposes of 
reproducing the failure, another approach is to temporarily rename the 
.git subdirectory to something else.

The above examples are from the current master branch @3d62df2.  They are 
from Mac OSX, but essentially identical failures also occur on Ubuntu 
14.04, CentOS 7, and Fedora 25.

These failures do not occur with the 1.6.2 release version, which may be 
due to a new bug, or may be due to differences between release and 
non-release builds.  In general, anything relying on git during builds 
should have a fallback for the non-git environment.

Fred Wright