Two macOS build fixes: EUC-JP encoding and tool building

[quarrel07]

macOS cannot currently build mk64. There are three independent causes. Two of them are here, kept as separate commits so they can be taken separately if you prefer.

The third is the truncated IDO binaries under tools/ido-recomp/macos/. Those were in this PR originally and have been taken out, so this no longer touches any binary. queueRAM's suggestion of building IDO from source via ido-static-recomp looks like the better answer there and is worth doing on its own.

---

1. macOS iconv corrupts the EUC-JP sources, so no version can byte-match.

macOS iconv converts a backslash that follows Japanese text into the fullwidth reverse solidus (0xA1C0) instead of leaving it as 0x5C. GNU iconv leaves it alone, which is why this has never shown up on Linux. It bites in src/cpu_vehicles_camera_path.c:219:

char* D_800EB710 = "ゴール直後の強制ソート\n";

The trailing \n becomes a literal two-byte character rather than an escape. 26 of the file's 199 backslashes are converted (0x5C: 199 -> 173, 0xA1C0: 0 -> 26), the generated file grows by exactly 26 bytes, .main grows with it, and the ROM shifts:

First difference at ROM addr 0x1008, in entry_point
Instruction difference at ROM addr 0xec328, in build/us/src/cpu_vehicles_camera_path.jp.o
Tons of differences, must be a shifted ROM.

Python's euc_jp codec produces the bytes the cartridge actually has, and PYTHON is already a required build dependency. For the other two EUC-JP sources macOS iconv and Python output are byte-identical, so this only changes behaviour where iconv was wrong. Should be a no-op on Linux.

---

2. The tools are built with bare make, which on macOS is 3.81.

tools/Makefile:51 generates its per-tool rules with define COMPILE =, which is 3.82 syntax. Under 3.81 those rules never take effect, so make falls back to its built-in %: %.c rule and links each tool from its first source file alone. n64graphics_SOURCES := n64graphics.c utils.c, so utils.c is dropped:

Undefined symbols for architecture arm64:
  "_g_verbosity", referenced from:
      _rgba2raw in n64graphics-7584c8.o
make[1]: *** [n64graphics] Error 1

Nothing there suggests the make version is at fault. docs/basics/compiling.md already tells macOS users to build with gmake, but Makefile:201 then calls bare make and undoes it. The root makefile uses !=, which needs make 4.0, so $(MAKE) is always new enough.

---

Verification. macOS 26.6, Apple Silicon. With these two, and IDO built from source with decompals/ido-static-recomp instead of the checked-in binaries, make reports mk64.us: OK (579c48e2...), make VERSION=eu.v10 reports mk64.eu.v10: OK (a72903945...), and eu.v11 matches too. Before these two fixes the US ROM came out as d2eaf74b99f3f2bc78fa5acc610fcb5e0ce39610.