Add note of `bc` dependency
Created by: hyshka
Without bc
installed on Arch Linux build fails:
MKELF scripts/mod/elfconfig.h
HOSTCC scripts/mod/modpost.o
HOSTCC scripts/mod/file2alias.o
HOSTCC scripts/mod/sumversion.o
CC kernel/bounds.s
/bin/sh: bc: command not found
make[1]: *** [Kbuild:42: include/generated/timeconst.h] Error 127
make[1]: *** Waiting for unfinished jobs....
HOSTCC scripts/dtc/fstree.o
HOSTCC scripts/dtc/data.o
HOSTCC scripts/dtc/livetree.o
HOSTCC scripts/dtc/treesource.o
make: *** [Makefile:1081: prepare0] Error 2
make: *** Waiting for unfinished jobs....
HOSTCC scripts/dtc/srcpos.o
HOSTCC scripts/dtc/checks.o
HOSTCC scripts/dtc/util.o
YACC scripts/dtc/dtc-parser.tab.h
LEX scripts/dtc/dtc-lexer.lex.c
YACC scripts/dtc/dtc-parser.tab.c
HOSTCC scripts/dtc/dtc-parser.tab.o
HOSTCC scripts/dtc/dtc-lexer.lex.o
HOSTLD scripts/mod/modpost
HOSTLD scripts/dtc/dtc
Compilation failed