ARMv4T (GBA) and ARMv6K (3DS) support (#75)

* Initial ARM support

* Disassemble const pool reloc

* Disasm ARM/Thumb/data based on mapping symbols

* Fallback to mapping symbol `$a`

* Support multiple DWARF sequences

* Update line info

* Rework DWARF line info parsing

- Properly handles multiple sections
  in DWARF 1
- line_info moved into ObjSection
- DWARF 2 parser no longer errors with
  no .text section
- Both parsers properly skip empty
  sections

* Simplify line_info (no Option)

* Get line info from section; output formatted ins string

* Unwrap code section in `arm.rs`

* Handle reloc `R_ARM_SBREL32`

* Update ARM disassembler

* Update README.md

* Format

* Revert "Update README.md"

This reverts commit 8bbfcc6f45.

* Update README.md

* Detect ARM version; support ARMv4T and v6K

* Combobox to force ARM version

* Clear LSB in ARM symbol addresses

* Support big-endian ARM ELF files

* Bump `unarm`, `arm-attr`

* Handle ARM implicit addends

* Update README.md

* Explicitly handle all ARM argument types

* Format

* Display more ARM relocs

* Mask LSB on ARM code symbols only

* Read ARM implicit addends

* Format

---------

Co-authored-by: Luke Street <luke.street@encounterpc.com>

objdiff-core/src/diff/mod.rs

@@ -93,6 +93,30 @@ pub enum MipsInstrCategory {
     R5900,
 }
 
+#[derive(
+    Debug,
+    Copy,
+    Clone,
+    Default,
+    Eq,
+    PartialEq,
+    serde::Deserialize,
+    serde::Serialize,
+    strum::VariantArray,
+    strum::EnumMessage,
+)]
+pub enum ArmArchVersion {
+    #[default]
+    #[strum(message = "Auto (default)")]
+    Auto,
+    #[strum(message = "ARMv4T (GBA)")]
+    V4T,
+    #[strum(message = "ARMv5TE (DS)")]
+    V5TE,
+    #[strum(message = "ARMv6K (3DS)")]
+    V6K,
+}
+
 #[inline]
 const fn default_true() -> bool { true }
 
@@ -108,6 +132,8 @@ pub struct DiffObjConfig {
     // MIPS
     pub mips_abi: MipsAbi,
     pub mips_instr_category: MipsInstrCategory,
+    // ARM
+    pub arm_arch_version: ArmArchVersion,
 }
 
 impl Default for DiffObjConfig {
@@ -119,6 +145,7 @@ impl Default for DiffObjConfig {
             x86_formatter: Default::default(),
             mips_abi: Default::default(),
             mips_instr_category: Default::default(),
+            arm_arch_version: Default::default(),
         }
     }
 }