Dpkg::Shlibs::Objdump: Mask ABI bits in flags for ARM

These are too unreliable for exact matches. There are objects with
EABIv4 in the wild, even when the current is EABIv5. The soft and
hard float flags are not always set on armel and armhf respectively,
although the Tag_ABI_VFP_args attribute in the the ARM attribute
section should always be present on armhf. And there are cases were
both soft and hard float flags are set at the same time(!).

Mask all flags on ARM, so that we get back to the previous behavior
with objdump. We can try to revisit this for a better matching during
the dpkg 1.19.x cycle.

Closes: #853793

debian/changelog

@@ -4,6 +4,9 @@ dpkg (1.18.22) UNRELEASED; urgency=medium
   * Turn status file parser errors on bogus field blank lines into warnings,
     otherwise the system cannot be easily recovered from. Regression
     introduced in dpkg 1.16.1. Reported by Jay Freeman <saurik@saurik.com>.
+  * Perl modules:
+    - Mask ARM ABI bits in the ELF processor flags in Dpkg::Shlibs::Objdump.
+      These are too unreliable to be used for exact matching. Closes: #853793
 
   [ Updated programs translations ]
   * Turkish (Mert Dirik). Closes: #853202

scripts/Dpkg/Shlibs/Objdump.pm

@@ -165,9 +165,6 @@ my %elf_mach_map = (
 # always better to not mask a flag, because that preserves the historical
 # behavior, and we do not drop dependencies.
 my %elf_flags_mask = (
-    ELF_MACH_ARM()      => ELF_FLAG_ARM_EABI_MASK |
-                           ELF_FLAG_ARM_NEW_ABI | ELF_FLAG_ARM_OLD_ABI |
-                           ELF_FLAG_ARM_SOFT_FLOAT | ELF_FLAG_ARM_HARD_FLOAT,
     ELF_MACH_IA64()     => ELF_FLAG_IA64_ABI64,
     ELF_MACH_MIPS()     => ELF_FLAG_MIPS_ABI_MASK | ELF_FLAG_MIPS_ABI2,
     ELF_MACH_PPC64()    => ELF_FLAG_PPC64_ABI64,