libsysdecode: Migrate from COMPAT_32BIT to generic COMPAT_LIBCOMPAT

The use isn't any more generic, just the variable itself, which will
allow COMPAT_32BIT to be removed. The fact we even have to check
COMPAT_LIBCOMPAT here in order to pass the right flags to CPP points at
our libcompat infrastructure not suitably modifying the CPP variable
(which we barely use for world; this and bsd.symver.mk are the two
uses, and the latter could benefit from the right flags too), but this
change doesn't attempt to fix that.

See commit 8fad2cda93c7 ("bsd.compat.mk: Provide new CPP and sub-make
variables") for the context behind this change.

Reviewed by:	emaste, imp, brooks, jhb
Differential Revision:	https://reviews.freebsd.org/D40930

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/libsysdecode/Makefile b/lib/libsysdecode/Makefile
index 6fb32caebcb1..eb977c3564ac 100644
--- a/lib/libsysdecode/Makefile
+++ b/lib/libsysdecode/Makefile
@@ -112,7 +112,8 @@ MLINKS+=sysdecode_mask.3 sysdecode_accessmode.3 \
 
 CLEANFILES= ioctl.c ioctl.c.tmp tables.h tables_linux.h
 
-.if defined(COMPAT_32BIT)
+# XXX: The flags should come from bsd.compat.mk / Makefile.libcompat
+.if ${COMPAT_LIBCOMPAT:U} == "32"
 CPP+=	-m32
 .endif