common: fix libpmem CFLAGS

For libpmem CFLAGS are set before the src/Makefile.inc is included.
As far as I can tell it was unintentionally introduced by #4797.
This oversight excluded libpmem from using DEFAULT_CFLAGS. Which has
significant consequences on the outcome e.g. restoring the use of
DEFAULT_CFLAGS reduces the maximum stack usage from 50kB to 8kB.

The issue is present in releases >= 1.9. Note that non-NDCTL builds
were not affected.

This regression although unintentional might had a not yet known
influence on the performance.

Signed-off-by: Jan Michalski <jan.michalski@intel.com>

ChangeLog

@@ -1,7 +1,7 @@
  * Unreleased *
 
  This release:
- - ...
+ - Significantly reduces the libpmem's stack usage.
 
 Tue Aug 8 2023 Oksana Sałyk <oksana.salyk@intel.com>
 

src/Makefile.inc

@@ -4,6 +4,9 @@
 # src/Makefile.inc -- common Makefile rules for PMDK
 #
 
+# Note: Please do not set CFLAGS before this file is included unless you do not
+# want to use default CFLAGS.
+
 TOP := $(dir $(lastword $(MAKEFILE_LIST)))..
 
 include $(TOP)/src/common.inc

src/libpmem/Makefile

@@ -50,8 +50,6 @@ ifeq ($(OS_DIMM),ndctl)
 SOURCE +=\
  region_namespace_ndctl.c\
  numa_ndctl.c
-CFLAGS += $(LIBNDCTL_CFLAGS)
-LIBS += $(LIBNDCTL_LIBS)
 else
 SOURCE +=\
  region_namespace_none.c\
@@ -68,5 +66,5 @@ include ../Makefile.inc
 
 include $(PMEM2)/$(ARCH)/flags.inc
 
-CFLAGS += -I.
-LIBS += -pthread
+CFLAGS += -I. $(LIBNDCTL_CFLAGS)
+LIBS += -pthread $(LIBNDCTL_LIBS)