hdr-check: make it work on Windows

On Windows, we define a specific set of pre-processor macros, among
other reasons: to avoid including syslog.h (which is not available on
Windows).

The hdr-check target did not use those definitions, resulting in a
failure to include said syslog.h.

To fix that, let's let the hdr-check target make use of ALL_CFLAGS,
which does include the pre-processor macros that would e.g. skip the
conditional block including syslog.h.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

Makefile

@@ -2772,7 +2772,7 @@ CHK_HDRS = $(filter-out $(EXCEPT_HDRS),$(patsubst ./%,%,$(LIB_H)))
 HCO = $(patsubst %.h,%.hco,$(CHK_HDRS))
 
 $(HCO): %.hco: %.h FORCE
-	$(QUIET_HDR)$(CC) -include git-compat-util.h -I. -o /dev/null -c -xc $<
+	$(QUIET_HDR)$(CC) $(ALL_CFLAGS) -include git-compat-util.h -I. -o /dev/null -c -xc $<
 
 .PHONY: hdr-check $(HCO)
 hdr-check: $(HCO)