Merge branch 'ps/clar-unit-test'

Import clar unit tests framework libgit2 folks invented for our
use.

* ps/clar-unit-test:
  Makefile: rename clar-related variables to avoid confusion
  clar: add CMake support
  t/unit-tests: convert ctype tests to use clar
  t/unit-tests: convert strvec tests to use clar
  t/unit-tests: implement test driver
  Makefile: wire up the clar unit testing framework
  Makefile: do not use sparse on third-party sources
  Makefile: make hdr-check depend on generated headers
  Makefile: fix sparse dependency on GENERATED_H
  clar: stop including `shellapi.h` unnecessarily
  clar(win32): avoid compile error due to unused `fs_copy()`
  clar: avoid compile error with mingw-w64
  t/clar: fix compatibility with NonStop
  t: import the clar unit testing framework
  t: do not pass GIT_TEST_OPTS to unit tests with prove

diff --cc Makefile
index 275a5ee3c9fad205d3576a540d585e95bf5f6c11,4ef1f1dfe3d7189c776aa9b0b743681c80ef80ba..9cf2be070fa26b1339523ea5b345ddc2a3c64f2b
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -1352,9 -1357,7 +1362,8 @@@ UNIT_TEST_PROGRAMS += t-reftable-stac
  UNIT_TEST_PROGRAMS += t-reftable-tree
  UNIT_TEST_PROGRAMS += t-strbuf
  UNIT_TEST_PROGRAMS += t-strcmp-offset
- UNIT_TEST_PROGRAMS += t-strvec
  UNIT_TEST_PROGRAMS += t-trailer
 +UNIT_TEST_PROGRAMS += t-urlmatch-normalization
  UNIT_TEST_PROGS = $(patsubst %,$(UNIT_TEST_BIN)/%$X,$(UNIT_TEST_PROGRAMS))
  UNIT_TEST_OBJS = $(patsubst %,$(UNIT_TEST_DIR)/%.o,$(UNIT_TEST_PROGRAMS))
  UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o