[PATCH] Makefile: fix 'hdr-check' when GCRYPT not installed

If the GCRYPT_SHA256 build variable is not set, then the 'hdr-check'
target complains about the missing <gcrypt.h> header file. Add the
'sha256/gcrypt.h' header file to the exception list, if the build
variable is not defined. While here, replace the 'xdiff%' filter
pattern with 'xdiff/%' (and similarly for the compat pattern) since
the original pattern inadvertently excluded the 'xdiff-interface.h'
header.

Signed-off-by: Ramsay Jones <redacted>
---

Hi Junio,

In my local 'hdr-check-fixup' branch, the gcrypt failure is fixed
almost by default. However, given that we are going the 'git ls-files'
route, this patch will fix it up.

Thanks!

ATB,
Ramsay Jones

 Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index c5240942f2..fbc84cb541 100644
--- a/Makefile
+++ b/Makefile

@@ -2736,7 +2736,10 @@ $(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
 sparse: $(SP_OBJ)
 
 GEN_HDRS := command-list.h unicode-width.h
-EXCEPT_HDRS := $(GEN_HDRS) compat% xdiff%
+EXCEPT_HDRS := $(GEN_HDRS) compat/% xdiff/%
+ifndef GCRYPT_SHA256
+	EXCEPT_HDRS += sha256/gcrypt.h
+endif
 CHK_HDRS = $(filter-out $(EXCEPT_HDRS),$(patsubst ./%,%,$(LIB_H)))
 HCO = $(patsubst %.h,%.hco,$(CHK_HDRS))
 

-- 
2.21.0