fs/ntfscomp.c:82:11: error: ‘flg’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

[PGNet Dev]

building

        cd grub
        git log | head -n5
                commit 552c9fd08122a3036c724ce96dfe68aa2f75705f
                Author: Patrick Steinhardt <address@hidden>
                Date:   Sat Mar 7 17:29:09 2020 +0100

                    gnulib: Fix build of base64 when compiling with memory 
debugging

with

        gcc --version
                gcc (SUSE Linux) 10.0.1 20200324 (experimental) [revision 
75c24a08d697d6442fe6c26142f0559f803af977]

patched

        patch -p1 < 
/tmp/grub_patches/grub_patches/0001-mdraid1x_linux-Fix-gcc10-error-Werror-array-bounds.patch
                patching file grub-core/disk/mdraid1x_linux.c
        patch -p1 < 
/tmp/grub_patches/grub_patches/0002-zfs-Fix-gcc10-error-Werror-zero-length-bounds.patch
                patching file grub-core/fs/zfs/zfs.c
                patching file include/grub/zfs/zap_leaf.h

from

        https://lists.gnu.org/archive/html/grub-devel/2020-03/msg00222.html

config's ok

        unset CC CPP
        ./bootstrap
        ./autogen.sh
        ./configure

build FAILs

        make V=1

                gcc -DHAVE_CONFIG_H -I.  -Wall -W -DGRUB_UTIL=1 
-D_FILE_OFFSET_BITS=64 -I./include -DGRUB_FILE=\"grub-core/fs/ntfscomp.c\" -I. 
-I. -I. -I. -I./include -I./include -I./grub-core/lib/libgcrypt-grub/src/  
-I./grub-core/lib/minilzo -I./grub-core/lib/xzembed -I./grub-core/lib/zstd 
-DMINILZO_HAVE_CONFIG_H -O3 -Wall -fstack-protector-strong -funwind-tables 
-fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches 
-march=native -mtune=native -D_FORTIFY_SOURCE=2 -D_FILE_OFFSET_BITS=64 -Wall -W 
-Wshadow -Wpointer-arith -Wundef -Wchar-subscripts -Wcomment 
-Wdeprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Wfloat-equal 
-Wformat-extra-args -Wformat-security -Wformat-y2k -Wimplicit 
-Wimplicit-function-declaration -Wimplicit-int -Wmain -Wmissing-braces 
-Wmissing-format-attribute -Wmultichar -Wparentheses -Wreturn-type 
-Wsequence-point -Wshadow -Wsign-compare -Wswitch -Wtrigraphs -Wunknown-pragmas 
-Wunused -Wunused-function -Wunused-label -Wunused-parameter -Wunused-value  
-Wunused-variable -Wwrite-strings -Wnested-externs -Wstrict-prototypes 
-Wcast-align  -Wextra -Wattributes -Wendif-labels -Winit-self 
-Wint-to-pointer-cast -Winvalid-pch -Wmissing-field-initializers -Wnonnull 
-Woverflow -Wvla -Wpointer-to-int-cast -Wstrict-aliasing -Wvariadic-macros 
-Wvolatile-register-var -Wpointer-sign -Wmissing-include-dirs 
-Wmissing-prototypes -Wmissing-declarations -Wformat=2 -Werror  -fno-builtin 
-Wno-undef -O3 -Wall -fstack-protector-strong -funwind-tables 
-fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches 
-march=native -mtune=native -MT grub-core/fs/libgrubmods_a-ntfscomp.o -MD -MP 
-MF grub-core/fs/.deps-util/libgrubmods_a-ntfscomp.Tpo -c -o 
grub-core/fs/libgrubmods_a-ntfscomp.o `test -f 'grub-core/fs/ntfscomp.c' || 
echo './'`grub-core/fs/ntfscomp.c
                grub-core/fs/ntfscomp.c: In function ‘read_block’:
                grub-core/fs/ntfscomp.c:82:11: error: ‘flg’ may be used 
uninitialized in this function [-Werror=maybe-uninitialized]
                   82 |       if (flg & 0x8000)
                      |           ^~~
                grub-core/fs/ntfscomp.c:74:17: note: ‘flg’ was declared here
                   74 |   grub_uint16_t flg, cnt;
                      |                 ^~~
                cc1: all warnings being treated as errors
                make[2]: *** [Makefile:7647: 
grub-core/fs/libgrubmods_a-ntfscomp.o] Error 1
                make[2]: Leaving directory '/usr/local/src/grub'
                make[1]: *** [Makefile:11920: all-recursive] Error 1
                make[1]: Leaving directory '/usr/local/src/grub'
                make: *** [Makefile:3772: all] Error 2