Build: for now, don't error on RWX loadable segments

Right now on some CI builds we get:

  aarch64-linux-gnu-gcc -nostdlib -fPIC -Wl,--warn-common -Wl,--no-undefined \
  	-Wl,--fatal-warnings -Wl,-shared -Wl,-Bsymbolic -L/usr/lib64 \
  	-L/__w/certwrapper/certwrapper/gnu-efi/ -Wl,--build-id=sha1 \
  	-Wl,--hash-style=sysv  -o certmule.so certmule.o sbat_data.o  \
  	/usr/lib/gcc/aarch64-linux-gnu/12/libgcc.a \
  	-T /__w/certwrapper/certwrapper/elf_aarch64_efi.lds
  /usr/bin/aarch64-linux-gnu-ld: warning: certmule.so has a LOAD segment with RWX permissions
  collect2: error: ld returned 1 exit status
  make: *** [../Makefile:115: certmule.so] Error 1

Right now this breaks CI despite no code change from when CI worked (due
to the distros being updated).  The segments themselves don't really
matter (they exist in ELF but not in PE), so we could plausibly fix
them, but that belongs in a different patch series.  Unfortunately some
of the linkers we're testing against don't support
"--no-warn-rwx-segments", and some of them don't support
"--no-error-rwx-segments".  So for right now, I'm disabling
"--fatal-warnings" instead.

Signed-off-by: Peter Jones <[email protected]>

Makefile

@@ -25,7 +25,7 @@ BUILDFLAGS := $(CFLAGS) -fPIC -Werror -Wall -Wextra -fshort-wchar \
 	-I$(GNUEFIDIR)/inc/$(ARCH) \
 	-I$(GNUEFIDIR)/inc/protocol
 CCLDFLAGS ?= -nostdlib -fPIC -Wl,--warn-common \
-        -Wl,--no-undefined -Wl,--fatal-warnings \
+        -Wl,--no-undefined \
         -Wl,-shared -Wl,-Bsymbolic -L$(LIBDIR) -L$(GNUEFIDIR) \
         -Wl,--build-id=sha1 -Wl,--hash-style=sysv
 LD = $(CROSS_COMPILE)ld