build(macos): inline homebrew deps in setup script, drop px4-dev meta-formula

Homebrew 4.5 (April 2026) stopped auto-tapping cross-tap
dependencies declared in formulae, as a security + performance
change. The px4-dev meta-formula pulled in packages from
osx-cross/arm, PX4/px4, and discoteq/discoteq, so 'brew install
px4-dev' now aborts before any real work unless every tap has been
added explicitly. On macos-latest CI runners the chain broke at the
first unreachable dep (discoteq/discoteq/flock) and subsequent make
steps failed with 'ccache: command not found'.

Since Tools/setup/macos.sh is the canonical install path and already
tapped osx-cross/arm and PX4/px4 before calling brew install, the
simplest fix is to inline the package list and call brew install
directly. The px4-dev meta-formula will be kept upstream as a
deprecated no-op so older copies of macos.sh on long-lived branches
and cached Docker images keep working.

The inlined package list is the same set px4-dev depended on, minus
the dead-weight flock dependency that hadn't been invoked in the PX4
build since the NuttX 9.1.x era. See the accompanying PX4/homebrew-px4
PR for formula changes.

Docs updated to match: docs/en/dev_setup/dev_env_mac.md no longer
names the px4-dev formula, describes the package list directly.

Verified locally on macOS ARM64:
- ./Tools/setup/macos.sh runs to completion with both taps and all 13
  packages resolving correctly
- make distclean && make px4_fmu-v6x_default builds successfully
  (1250/1250 ninja steps, 1930096 B FLASH used)

Signed-off-by: Ramon Roche <mrpollo@gmail.com>

Tools/setup/macos.sh

@@ -40,32 +40,44 @@ then
 	/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
 fi
 
-# Install px4-dev formula
+# Required taps. Homebrew 4.5+ no longer auto-resolves cross-tap
+# dependencies, so every tap that a package lives in must be added
+# explicitly here before `brew install`.
+#
+# - osx-cross/arm: arm-gcc-bin@13 (ARM cross-compiler)
+# - PX4/px4:       fastdds, genromfs, kconfig-frontends (PX4-specific)
+brew tap osx-cross/arm
+brew tap PX4/px4
+
+# Package list. This replaces the px4-dev meta-formula, which is kept
+# as a deprecated no-op upstream. See PX4/homebrew-px4 for history.
+PX4_BREW_PACKAGES=(
+	ant
+	astyle
+	bash-completion
+	ccache
+	cmake
+	fastdds
+	genromfs
+	kconfig-frontends
+	ncurses
+	ninja
+	osx-cross/arm/arm-gcc-bin@13
+	python
+	python-tk
+)
+
 if [[ $REINSTALL_FORMULAS == "--reinstall" ]]; then
-	echo "[macos.sh] Re-installing dependencies (homebrew px4-dev)"
-
-	# confirm Homebrew installed correctly
+	echo "[macos.sh] Re-installing PX4 toolchain dependencies"
 	brew doctor
-
-	brew tap osx-cross/arm
-	brew tap PX4/px4
-
-	brew reinstall px4-dev
-	brew link --overwrite --force arm-gcc-bin@13
+	brew reinstall "${PX4_BREW_PACKAGES[@]}"
 else
-	if brew ls --versions px4-dev > /dev/null; then
-		echo "[macos.sh] px4-dev already installed"
-	else
-		echo "[macos.sh] Installing general dependencies (homebrew px4-dev)"
-
-		brew tap osx-cross/arm
-		brew tap PX4/px4
-
-		brew install px4-dev
-		brew link --overwrite --force arm-gcc-bin@13
-	fi
+	echo "[macos.sh] Installing PX4 toolchain dependencies"
+	brew install "${PX4_BREW_PACKAGES[@]}"
 fi
 
+brew link --overwrite --force arm-gcc-bin@13
+
 # Python dependencies
 echo "[macos.sh] Installing Python3 dependencies"
 # We need to have future to install pymavlink later.

docs/en/dev_setup/dev_env_mac.md

@@ -59,7 +59,7 @@ To build for [other targets](../dev_setup/dev_env.md#supported-targets) you will
    ```
 
    This installs:
-   - **`px4-dev`** — ARM cross-compiler (`arm-gcc-bin@13`), `cmake`, `ninja`, `ccache`, and other build tools
+   - **Toolchain packages** from the `osx-cross/arm` and `PX4/px4` Homebrew taps — ARM cross-compiler (`arm-gcc-bin@13`), `cmake`, `ninja`, `ccache`, `fastdds`, `genromfs`, `kconfig-frontends`, and other build tools
    - **Python packages** from `requirements.txt`
    - **`px4-sim`** (via `--sim-tools`) — Gazebo Harmonic simulation (`gz-harmonic`) and related tools