Unconditionally enable debugging for libzpool

We already enable -DDEBUG unconditionally (meaning regardless
of this is a debug build or a performance build) for zdb and
ztest as they are mostly used for development and debugging.

This patch enables -DDEBUG for libzpool extending the debugging
checks for zdb, ztest, and a couple of other test utilities.

In addition to passing -DDEBUG we also enable -DZFS_DEBUG so
all assertion checks work s expected. We do so not only in
libzpool but in every utility that links to it, even if the
utility doesn't directly use any functionality wrapped in
ZFS_DEBUG macro definitions. The reason is that these utilities
may still include headers that contain structs that have more
fields when ZFS_DEBUG is defined. This can be a problem as
enabling that flag for libzpool but not for zdb can lead into
random problems (e.g. segmentation faults) as zdb may be have
an incorrect view of a struct passed to it by libzpool.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10549

cmd/raidz_test/Makefile.am

@@ -4,7 +4,7 @@ include $(top_srcdir)/config/Rules.am
 AM_CFLAGS += $(FRAME_LARGER_THAN)
 
 # Unconditionally enable ASSERTs
-AM_CPPFLAGS += -DDEBUG -UNDEBUG
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
 
 bin_PROGRAMS = raidz_test
 

cmd/zdb/Makefile.am

@@ -1,7 +1,7 @@
 include $(top_srcdir)/config/Rules.am
 
 # Unconditionally enable debugging for zdb
-AM_CPPFLAGS += -DDEBUG -UNDEBUG
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
 
 sbin_PROGRAMS = zdb
 

cmd/zhack/Makefile.am

@@ -1,5 +1,8 @@
 include $(top_srcdir)/config/Rules.am
 
+# Unconditionally enable debugging for zhack
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
+
 sbin_PROGRAMS = zhack
 
 zhack_SOURCES = \

cmd/ztest/Makefile.am

@@ -7,7 +7,7 @@ AM_CFLAGS += $(NO_FORMAT_TRUNCATION)
 AM_CFLAGS += $(FRAME_LARGER_THAN)
 
 # Unconditionally enable ASSERTs
-AM_CPPFLAGS += -DDEBUG -UNDEBUG
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
 
 sbin_PROGRAMS = ztest
 

lib/libzpool/Makefile.am

@@ -7,6 +7,9 @@ VPATH = \
 	$(top_srcdir)/module/os/linux/zfs \
 	$(top_srcdir)/lib/libzpool
 
+# Unconditionally enable debugging for libzpool
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
+
 # Suppress unused but set variable warnings often due to ASSERTs
 AM_CFLAGS += $(NO_UNUSED_BUT_SET_VARIABLE)
 

tests/zfs-tests/cmd/btree_test/Makefile.am

@@ -22,7 +22,7 @@ DEFAULT_INCLUDES += \
 	-I$(top_srcdir)/lib/libspl/include
 
 # Unconditionally enable ASSERTs
-AM_CPPFLAGS += -DDEBUG -UNDEBUG
+AM_CPPFLAGS += -DDEBUG -UNDEBUG -DZFS_DEBUG
 
 pkgexec_PROGRAMS = btree_test
 btree_test_SOURCES = btree_test.c