x86: garbage collect section if not debugging

boards/qemu-i386/Makefile.include

@@ -11,9 +11,6 @@ DEBUGGER = $(TERMPROG)
 
 all:
 
-all-debug: export CFLAGS += -ggdb3 -O0
-all-debug: all
-
 debug-kdbg: DEBUGGER_FLAGS="kdbg -r :1234 -- $(ELFFILE)"
 debug-kdbg: debug
 
@@ -26,4 +23,4 @@ debug-tui: debug
 debug-gdb: debug
 DEBUGGER_FLAGS = "x-terminal-emulator -e gdb -ex 'target remote :1234' --args $(ELFFILE)"
 
-debug: 
+debug:

boards/x86-multiboot-common/Makefile.include

@@ -55,12 +55,18 @@ export OFLAGS = -O binary
 LINKFLAGS += -m32 -nostdlib -nostdinc -nostartfiles -nodefaultlibs \
              --prefix=$(NEWLIB_BASE) \
              -Wl,-rpath,$(NEWLIB_BASE)/lib \
-             -T $(RIOTBASE)/boards/x86-multiboot-common/linker.ld
+             -T$(RIOTBASE)/boards/x86-multiboot-common/linker.ld
 UNDEF += $(BINDIR)x86-multiboot-common_base/startup.o
 
-#CFLAGS += -ffunction-sections -fdata-sections
-#LINKFLAGS += -Wl,--gc-sections
-#CFLAGS += -Wall -Wextra -Werror -pedantic -pedantic-errors \
-
 BASELIBS += $(NEWLIB_BASE)/lib/libc.a \
             $(NEWLIB_BASE)/lib/libm.a
+
+all:
+
+all-debug: export CFLAGS += -ggdb3 -O0
+all-debug: all
+
+ifeq (, $(filter all-debug, $(MAKECMDGOALS)))
+  CFLAGS += -Os -ffunction-sections -fdata-sections
+  LINKFLAGS += -Wl,--gc-sections
+endif

boards/x86-multiboot-common/linker.ld

@@ -34,7 +34,7 @@ SECTIONS
        Next we'll put the .text section. */
     ._multiboot_header :
     {
-        *(._multiboot_header)
+        KEEP(*(._multiboot_header))
     }
 
     .note.gnu.build-id :