Re-enable -Werror again.

This time, change the default CFLAGS to match the simple defaults that
the tinderboxes use. That is, don't use -fno-strict-aliasing by default.

My last attempt to re-anable -Werror gave me a lesson in what strict
aliasing is all about. There was code in libthr that wasn't 64-bit clean.
The default use of -fno-strict-aliasing hid that.

By using -fno-strict-aliasing by default we were choosing to ignore
problems in code which had the potential to shoot ourselves in the
foot. Sometimes it would be the 64-bit foot. I have both feet. The left
ones are 32 bits and the right ones are 64 bits. Don't ask about my
endian orientation. :-)

The -fno-strict-aliasing compiler arg can still be used if NO_STRING_ALIASING
is define in make.

We are early in the FreeBSD 8 development, so we have the opportunity to
wait and see if this works for us. I am sure that people will complain.
We can easily revert this. All I ask is that we take sides: clean code or
not. YMMV.

Note that by using -fno-strict-aliasing the build won't actually break.
Only where WARNS is set (and -Werror is used) will a compiler warning break
the build. The use of WARNS levels implies (to me at least) that the
developer has taken some care to make the code pass basic checks. This
commit makes those checks just a little bit more strict.

1 files changed, 5 insertions, 2 deletions

diff --git a/share/mk/sys.mk b/share/mk/sys.mk
index b4dd8ed..a15331f 100644
--- a/share/mk/sys.mk
+++ b/share/mk/sys.mk
@@ -36,9 +36,12 @@ CFLAGS		?=	-O
 .else
 CC		?=	cc
 .if ${MACHINE_ARCH} == "arm"
-CFLAGS		?=	-O -fno-strict-aliasing -pipe
+CFLAGS		?=	-O -pipe
 .else
-CFLAGS		?=	-O2 -fno-strict-aliasing -pipe
+CFLAGS		?=	-O2 -pipe
+.endif
+.if defined(NO_STRICT_ALIASING)
+CFLAGS		+=	-fno-strict-aliasing
 .endif
 .endif