Back port part of r555665 | gerald | 2020-11-18 from lang/gcc10-devel:

Forward port part of r555542 | gerald | 2020-11-17 from lang/gcc9-devel:

    Fold the PLUGINS option, which has been on by default, into standard
    behavior and remove that option.  It has not been causing any issues
    since we enabled it 11 months ago, nor measurable overhead.

PR:		242644

lang/gcc10/Makefile

@@ -38,8 +38,8 @@ SSP_UNSAFE=	yes
 CFLAGS:=	${CFLAGS:N-mretpoline}
 CXXFLAGS:=	${CXXFLAGS:N-mretpoline}
 
-OPTIONS_DEFINE=		BOOTSTRAP GRAPHITE PLUGINS
-OPTIONS_DEFAULT=	BOOTSTRAP PLUGINS
+OPTIONS_DEFINE=		BOOTSTRAP GRAPHITE
+OPTIONS_DEFAULT=	BOOTSTRAP
 BOOTSTRAP_DESC=		Build using a full bootstrap
 GRAPHITE_DESC=		Support for Graphite loop optimizations
 
@@ -54,8 +54,6 @@ MULTILIB_CONFIGURE_ENABLE=	multilib
 CONFIGURE_ARGS+=	--disable-multilib
 .endif
 
-PLUGINS_CONFIGURE_ENABLE=	plugin
-
 .include <bsd.port.pre.mk>
 
 .if ${ARCH} == amd64
@@ -88,6 +86,7 @@ BINMODE=	755
 .endif
 CONFIGURE_ARGS+=--disable-nls \
 		--enable-gnu-indirect-function \
+		--enable-plugin \
 		--libdir=${TARGLIB} \
 		--libexecdir=${LIBEXEC} \
 		--program-suffix=${SUFFIX} \