elf2flt: don’t record the build date into the binaries’ header

while this already supports the SOURCE_DATE_EPOCH standard for
reproducible builds, and even setting it to 0, some other tools
choke on values below 1980, so instead patch out the recording
altogether, as it also compresses better

toolchain/elf2flt/patches/453398f917d167f8c308c8f997270c48ae8f8b12/0009-no-build-date.patch

@@ -0,0 +1,11 @@
+--- elf2flt-453398f917d167f8c308c8f997270c48ae8f8b12.orig/elf2flt.c	2025-04-14 19:50:51.016711969 +0000
++++ elf2flt-453398f917d167f8c308c8f997270c48ae8f8b12/elf2flt.c	2025-04-14 23:14:52.212092781 +0000
+@@ -2132,7 +2132,7 @@ int main(int argc, char *argv[])
+ 	  | (pic_with_got ? FLAT_FLAG_GOTPIC : 0)
+ 	  | (docompress ? (docompress == 2 ? FLAT_FLAG_GZDATA : FLAT_FLAG_GZIP) : 0)
+ 	  );
+-  hdr.build_date = htonl((uint32_t)get_build_date());
++  hdr.build_date = 0;
+   memset(hdr.filler, 0x00, sizeof(hdr.filler));
+ 
+   for (i=0; i<reloc_len; i++) reloc[i] = htonl(reloc[i]);