perf tools: Makefile: Remove various and sundry cruft

This commit squashes several commits that remove:

 unnecessary uname calls
 `sh -c'
 BUILT_INS and QUIET_BUILT_IN

    They have no effect, and the `fixup-builtins' and `check-builtins.sh'
    scripts don't even exist.

 RUNTIME_PREFIX

    It's currently never anything but unset, and it's apparently
    only meaningful when Microsoft Windows is the operating system
    (according to the source for git).

 TEST_PROGRAMS
 EXTRA_PROGRAMS
 unused SHELL_PATH_SQ portions
 unused test for V=2
 useless exports

    Only when `V' is undefined (that is, only when the value of `V'
    is empty) is `export V' performed, which just has the effect of
    placing the empty-valued variable `V' in the environment.

    The only other script to make use of `V' is `Documentation/Makefile',
    which only checks whether `V' is undefined (that is, whether the value
    of `V' is empty); hence, the `export V' has no effect whatsoever.

    Similarly, `export QUIET_GEN' is useless because it will only have
    a non-empty value when `V' has an empty-value, and when `V' has
    an empty-value, `QUIET_GEN' is always explicitly set in every
    script in which it is used.

    `DESTDIR' is only ever defined by the user via the environment
    or the command line, both of which are automatically exported
    to sub-make processes. Furthermore, no non-make sub-scripts
    make use of `DESTDIR' as an environment variable.

    No other scripts use `perfexec_instdir'.

 unused QUIET_SUBDIR{0,1}
 TAR and RPMBUILD
 PTHREAD_LIBS
 Maintainer's dist rules and commands
 distclean target
 Test suite coverage testing
 PRINT_DIR and NO_SUBDIR
 `configure' target
 NO_CURL
 @@PERF_VERSION@@ substitution

    Without the sed command, all of the rule's commands can be reduced
    to a single line that copies a file and sets the permissions properly
    in the process.

 `make test' echo line
 template_instdir
 PERF-BUILD-OPTIONS
 double-colon rules

    The use of double-colon rules seems misguided or vestigial git.

 Essentially hard-coded $(SCRIPTS) expansion

Signed-off-by: Michael Witten <mfwitten@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>