File allow-overriding-compiler-variables.patch of Package bmake

--- bmake/mk/sys/Linux.mk	2020-04-18 00:08:31.000000000 +0300
+++ Linux.mk	2020-05-16 19:05:25.000000000 +0300
@@ -8,76 +8,95 @@
 ROOT_GROUP=	root
 
 # would be better to work out where it is...
-LIBCRT0= /dev/null
+LIBCRT0?= /dev/null
 
-NEED_SOLINKS=yes
+NEED_SOLINKS?=yes
 
 .SUFFIXES: .out .a .ln .o .c ${CXX_SUFFIXES} .F .f .r .y .l .s .S .cl .p .h .sh .m4
 
 .LIBS:		.a
 
-AR=		ar
-ARFLAGS=	rl
-RANLIB=		ranlib
-
-AS=		as
-AFLAGS=
-COMPILE.s=	${AS} ${AFLAGS}
-LINK.s=		${CC} ${AFLAGS} ${LDFLAGS}
-COMPILE.S=	${CC} ${AFLAGS} ${CPPFLAGS} -c
-LINK.S=		${CC} ${AFLAGS} ${CPPFLAGS} ${LDFLAGS}
-.if exists(/usr/local/bin/gcc)
-CC=		gcc -pipe
-DBG=		-O -g
-STATIC?=		-static
-.else
-CC=             cc -pipe
-DBG=         -g
-STATIC=         -Bstatic
-.endif
-CFLAGS=		${DBG}
-COMPILE.c=	${CC} ${CFLAGS} ${CPPFLAGS} -c
-LINK.c=		${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}
-
-CXX=		g++
-CXXFLAGS=	${CFLAGS}
-COMPILE.cc=	${CXX} ${CXXFLAGS} ${CPPFLAGS} -c
-LINK.cc=	${CXX} ${CXXFLAGS} ${CPPFLAGS} ${LDFLAGS}
+AR?=		ar
+ARFLAGS?=	rl
+RANLIB?=	ranlib
+
+AS?=		as
+AFLAGS?=
+COMPILE.s?=	${CC} ${AFLAGS} -c
+LINK.s?=	${CC} ${AFLAGS} ${LDFLAGS}
+COMPILE.S?=	${CC} ${AFLAGS} ${CPPFLAGS} -c -traditional-cpp
+LINK.S?=	${CC} ${AFLAGS} ${CPPFLAGS} ${LDFLAGS}
+CC?=		gcc
+DBG?=		-O -g
+STATIC?=	-static
+CFLAGS?=	${DBG}
+COMPILE.c?=	${CC} ${CFLAGS} ${CPPFLAGS} -c
+LINK.c?=	${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}
+
+CXX?=		g++
+CXXFLAGS?=	${CFLAGS}
+COMPILE.cc?=	${CXX} ${CXXFLAGS} ${CPPFLAGS} -c
+LINK.cc?=	${CXX} ${CXXFLAGS} ${CPPFLAGS} ${LDFLAGS}
+
+OBJC?=		${CC}
+OBJCFLAGS?=	${CFLAGS}
+COMPILE.m?=	${OBJC} ${OBJCFLAGS} ${CPPFLAGS} -c
+LINK.m?=	${OBJC} ${OBJCFLAGS} ${CPPFLAGS} ${LDFLAGS}
 
-CPP=		cpp
+CPP?=		cpp
 .if defined(DESTDIR)
 CPPFLAGS+=	-nostdinc -idirafter ${DESTDIR}/usr/include
 .endif
 
-MK_DEP=	mkdeps.sh -N
-FC=		f77
-FFLAGS=		-O
-RFLAGS=
-COMPILE.f=	${FC} ${FFLAGS} -c
-LINK.f=		${FC} ${FFLAGS} ${LDFLAGS}
-COMPILE.F=	${FC} ${FFLAGS} ${CPPFLAGS} -c
-LINK.F=		${FC} ${FFLAGS} ${CPPFLAGS} ${LDFLAGS}
-COMPILE.r=	${FC} ${FFLAGS} ${RFLAGS} -c
-LINK.r=		${FC} ${FFLAGS} ${RFLAGS} ${LDFLAGS}
-
-LEX=		lex
-LFLAGS=
-LEX.l=		${LEX} ${LFLAGS}
-
-LD=		ld
-LDFLAGS=
-
-LINT=		lint
-LINTFLAGS=	-chapbx
-
-PC=		pc
-PFLAGS=
-COMPILE.p=	${PC} ${PFLAGS} ${CPPFLAGS} -c
-LINK.p=		${PC} ${PFLAGS} ${CPPFLAGS} ${LDFLAGS}
-
-YACC=		yacc
-YFLAGS=		-d
-YACC.y=		${YACC} ${YFLAGS}
+MK_DEP?=	mkdeps.sh -N
+FC?=		f77
+FFLAGS?=	-O
+RFLAGS?=
+COMPILE.f?=	${FC} ${FFLAGS} -c
+LINK.f?=	${FC} ${FFLAGS} ${LDFLAGS}
+COMPILE.F?=	${FC} ${FFLAGS} ${CPPFLAGS} -c
+LINK.F?=	${FC} ${FFLAGS} ${CPPFLAGS} ${LDFLAGS}
+COMPILE.r?=	${FC} ${FFLAGS} ${RFLAGS} -c
+LINK.r?=	${FC} ${FFLAGS} ${RFLAGS} ${LDFLAGS}
+
+INSTALL?=	install
+
+LEX?=		lex
+LFLAGS?=
+LEX.l?=		${LEX} ${LFLAGS}
+
+LD?=		ld
+LDFLAGS?=
+
+LINT?=		lint
+LINTFLAGS?=	-chapbxzF
+
+LORDER?=	echo
+
+MAKE?=		bmake
+
+NM?=		nm
+
+PC?=		pc
+PFLAGS?=
+COMPILE.p?=	${PC} ${PFLAGS} ${CPPFLAGS} -c
+LINK.p?=	${PC} ${PFLAGS} ${CPPFLAGS} ${LDFLAGS}
+
+SHELL?=		sh
+
+SIZE?=		size
+
+TSORT?= 	tsort
+
+YACC?=		yacc
+YFLAGS?=	-d
+YACC.y?=	${YACC} ${YFLAGS}
+
+# At least Ubuntu 8.1 sets __attribute__((warn_unused_result)) on fwrite()
+# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25509
+.if !defined(NOGCCERROR)
+CFLAGS+= -Wno-error
+.endif
 
 # C
 .c:
@@ -88,6 +107,8 @@
 	${COMPILE.c} ${.IMPSRC}
 	${AR} ${ARFLAGS} $@ $*.o
 	rm -f $*.o
+.c.ln:
+	${LINT} ${LINTFLAGS} ${CPPFLAGS:M-[IDU]*} -i ${.IMPSRC}
 
 # C++
 ${CXX_SUFFIXES}: