Drop unused sections when linking HULK

Rsconscript

@@ -136,7 +136,7 @@ hulk_env = env "hulk", use: %w[ldc2 x86_64-elf-gcc] do |env|
   env["D_IMPORT_PATH"] += %w[src]
   env["D_IMPORT_PATH"] << env.expand("^/src")
   env["LD"] = "x86_64-elf-gcc"
-  env["LDFLAGS"] += %w[-nostdlib -Tsrc/hulk/hulk.ld -Wl,-Map,${_TARGET}.map]
+  env["LDFLAGS"] += %w[-nostdlib -Tsrc/hulk/hulk.ld -Wl,--gc-sections -Wl,-Map,${_TARGET}.map]
   env["LDCMD"] = %w[${LD} -o ${_TARGET} ${LDFLAGS} ${_SOURCES} ${LIBDIRPREFIX}${LIBPATH} ${LIBLINKPREFIX}${LIBS}]
   env["OBJDUMP"] = "x86_64-elf-objdump"
   env["OBJCOPY"] = "x86_64-elf-objcopy"

src/hulk/hulk.ld

@@ -6,7 +6,7 @@ SECTIONS
 
     .hulk_header :
     {
-        *(.hulk_header)
+        KEEP(*(.hulk_header))
     }
 
     . = ALIGN(4K);