mk/os.mk: don't use OS env var for overridingHEADmaster

If you want to override the OS or OS-detect command you can still use
_OS and _OS_SH, but OS is too common of an environment variable to
listen for.

Closes: https://bugs.gentoo.org/906171
Signed-off-by: Matoro Mahri <matoro_gentoo@matoro.tk>
Closes: https://github.com/gentoo/netifrc/pull/52
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mk/os.mk b/mk/os.mk
index c306f05..cf089e7 100644
--- a/mk/os.mk
+++ b/mk/os.mk
@@ -5,7 +5,7 @@
 
 _OS_SH=		uname -s
 _OS:= 		$(shell ${_OS_SH})
-OS?= 		${_OS}
+OS= 		${_OS}
 include ${MK}/os-${OS}.mk
 
 RC_LIB=		/$(LIBNAME)/rc