syslinux: Fix build with gcc10

Bring in a patch from fedora to fix -fno-common issue

(From OE-Core rev: 7457e6e2a2b0d00875c15112b6528c9ad97830d5)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit f635bd89d53cc8c110b18aa593babc55eeffc511)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/syslinux/syslinux/0010-Workaround-multiple-definition-of-symbol-errors.patch

@@ -0,0 +1,97 @@
+From 951928f2cad5682c2844e6bd0f7201236c5d9b66 Mon Sep 17 00:00:00 2001
+From: Merlin Mathesius <mmathesi@redhat.com>
+Date: Wed, 13 May 2020 08:02:27 -0500
+Subject: [PATCH] Workaround multiple definition of symbol errors
+
+Lifted from Fedora https://src.fedoraproject.org/rpms/syslinux/blob/master/f/0005-Workaround-multiple-definition-of-symbol-errors.patch
+
+Upstream-Status: Pending
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+
+---
+ com32/cmenu/Makefile           | 2 +-
+ com32/elflink/ldlinux/Makefile | 2 +-
+ com32/gpllib/Makefile          | 2 +-
+ com32/hdt/Makefile             | 2 +-
+ core/Makefile                  | 2 +-
+ dos/Makefile                   | 2 +-
+ efi/Makefile                   | 2 +-
+ 7 files changed, 7 insertions(+), 7 deletions(-)
+
+--- a/com32/cmenu/Makefile
++++ b/com32/cmenu/Makefile
+@@ -49,7 +49,7 @@ makeoutputdirs:
+ 	@mkdir -p $(OBJ)/libmenu
+ 
+ libmenu/libmenu.elf: $(LIBMENU)
+-	$(LD) -shared $(LDFLAGS) -soname $(patsubst %.elf,%.c32,$(@F)) \
++	$(LD) -shared $(LDFLAGS) -z muldefs -soname $(patsubst %.elf,%.c32,$(@F)) \
+ 		-o $@ $^
+ 
+ tidy dist:
+--- a/com32/elflink/ldlinux/Makefile
++++ b/com32/elflink/ldlinux/Makefile
+@@ -33,7 +33,7 @@ endif
+ all: $(BTARGET) ldlinux_lnx.a
+ 
+ ldlinux.elf : $(OBJS)
+-	$(LD) $(LDFLAGS) -soname $(SONAME) -o $@ $^ $(LIBS)
++	$(LD) $(LDFLAGS) -z muldefs -soname $(SONAME) -o $@ $^ $(LIBS)
+ 
+ LNXCFLAGS += -D__export='__attribute__((visibility("default")))'
+ LNXLIBOBJS = get_key.lo
+--- a/com32/gpllib/Makefile
++++ b/com32/gpllib/Makefile
+@@ -24,7 +24,7 @@ makeoutputdirs:
+ 		$(addprefix $(OBJ),$(sort $(dir $(LIBOBJS)))),$(b))
+ 
+ libgpl.elf : $(LIBOBJS)
+-	$(LD) -shared $(LDFLAGS) -soname $(patsubst %.elf,%.c32,$(@F)) -o $@ $^
++	$(LD) -shared $(LDFLAGS) -z muldefs -soname $(patsubst %.elf,%.c32,$(@F)) -o $@ $^
+ 
+ tidy dist clean:
+ 	find . \( -name \*.o -o -name .\*.d -o -name \*.tmp \) -print0 | \
+--- a/com32/hdt/Makefile
++++ b/com32/hdt/Makefile
+@@ -52,7 +52,7 @@ QEMU			?= qemu-kvm
+ all: $(MODULES) $(TESTFILES)
+ 
+ hdt.elf : $(OBJS) $(LIBS) $(C_LIBS)
+-	$(LD) $(LDFLAGS) -o $@ $^
++	$(LD) $(LDFLAGS) -z muldefs -o $@ $^
+ 
+ memtest:
+ 	-[ ! -f $(FLOPPY_DIR)/$(MEMTEST) ] && $(WGET) $(MEMTEST_URL) -O $(FLOPPY_DIR)/$(MEMTEST)
+--- a/core/Makefile
++++ b/core/Makefile
+@@ -156,7 +156,7 @@ LDSCRIPT = $(SRC)/$(ARCH)/syslinux.ld
+ NASM_ELF = elf
+ 
+ %.elf: %.o $(LIBDEP) $(LDSCRIPT) $(AUXLIBS)
+-	$(LD) $(LDFLAGS) -pie -Bsymbolic \
++	$(LD) $(LDFLAGS) -z muldefs -pie -Bsymbolic \
+ 		-T $(LDSCRIPT) \
+ 		--unresolved-symbols=report-all \
+ 		-E --hash-style=gnu -M -o $@ $< \
+--- a/dos/Makefile
++++ b/dos/Makefile
+@@ -19,7 +19,7 @@ include $(MAKEDIR)/embedded.mk
+ CFLAGS	+= -D__MSDOS__ -mregparm=3 -DREGPARM=3
+ # CFLAGS  += -DDEBUG
+ 
+-LDFLAGS	 = -T $(SRC)/dosexe.ld
++LDFLAGS	 = -T $(SRC)/dosexe.ld -z muldefs
+ OPTFLAGS = -g
+ INCLUDES = -include code16.h -nostdinc -iwithprefix include \
+ 	   -I$(SRC) -I$(SRC)/.. -I$(SRC)/../libfat \
+--- a/efi/Makefile
++++ b/efi/Makefile
+@@ -71,7 +71,7 @@ $(OBJS): | $(OBJ)/$(ARCH)
+ BTARGET  = syslinux.efi
+ 
+ syslinux.so: $(OBJS) $(CORE_OBJS) $(LIB_OBJS)
+-	$(LD) $(LDFLAGS) --strip-debug -o $@ $^ -lgnuefi -lefi
++	$(LD) $(LDFLAGS) -z muldefs --strip-debug -o $@ $^ -lgnuefi -lefi
+ 
+ # We need to rename the .hash section because the EFI firmware
+ # linker really doesn't like it.

meta/recipes-devtools/syslinux/syslinux_6.04-pre2.bb

@@ -20,6 +20,7 @@ SRC_URI = "https://www.zytor.com/pub/syslinux/Testing/6.04/syslinux-${PV}.tar.xz
            file://0007-linux-syslinux-implement-ext_construct_sectmap_fs.patch \
            file://0008-libinstaller-syslinuxext-implement-syslinux_patch_bo.patch \
            file://0009-linux-syslinux-implement-install_bootblock.patch \
+           file://0010-Workaround-multiple-definition-of-symbol-errors.patch \
            file://0001-install-don-t-install-obsolete-file-com32.ld.patch \
            "