Remove trailing tab in `build_config/dreamcast_shelf.rb` [ci skip]

build_config/dreamcast_shelf.rb

@@ -20,7 +20,7 @@ MRuby::CrossBuild.new("dreamcast") do |conf|
   # C compiler
   # Flags were extracted from KallistiOS environment files
   conf.cc do |cc|
-    cc.command = "#{BIN_PATH}/sh-elf-gcc"	
+    cc.command = "#{BIN_PATH}/sh-elf-gcc"
     cc.include_paths << ["#{KOS_PATH}/include", "#{KOS_PATH}/kernel/arch/dreamcast/include", "#{KOS_PATH}/addons/include", "#{KOS_PATH}/../kos-ports/include"]
     cc.flags << ["-O2", "-fomit-frame-pointer", "-ml", "-m4-single-only", "-ffunction-sections", "-fdata-sections", "-Wall", "-g", "-fno-builtin", "-ml", "-m4-single-only", "-Wl,-Ttext=0x8c010000", "-Wl,--gc-sections", "-T#{KOS_PATH}/utils/ldscripts/shlelf.xc", "-nodefaultlibs"]
     cc.compile_options = %Q[%{flags} -o "%{outfile}" -c "%{infile}"]