Add ARM platforms to the build script

scripts/automator/build/compiler-defaults

@@ -5,10 +5,10 @@ cc=""
 cxx=""
 ld=""
 ranlib=""
-cflags=(-Wall -pipe)
-cxxonly=("")
-ldflags=("")
-libs=("")
+cflags+=(-Wall -pipe)
+cxxonly+=("")
+ldflags+=("")
+libs+=("")
 
 # Use ccache if it's available
 if command -v ccache &> /dev/null; then

scripts/automator/build/gcc-linux_armv7_mali

@@ -0,0 +1,2 @@
+# GCC flags for generically identified ARMv7 MALI SBCs
+cflags_release+=(-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_imx6

@@ -0,0 +1,3 @@
+# GCC flags specific to NXP's series of i.MX 6 SBCs
+cflags_release+=(-march=armv7-a -mfpu=neon -mtune=cortex-a9 
+                 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_odroid_c1

@@ -0,0 +1,2 @@
+# GCC flags specific to Hardkernel Co's ODROID-C1 SBC
+cflags_release+=(-mcpu=cortex-a5 -mfpu=neon-vfpv4 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_odroid_c2

@@ -0,0 +1,3 @@
+# GCC flags specific to Hardkernel Co's ODROID-C2 SBC
+cflags_release+=(-march=armv8-a+crc -mtune=cortex-a53 
+                 -mfpu=neon-fp-armv8)

scripts/automator/build/gcc-linux_odroid_xu

@@ -0,0 +1,2 @@
+# GCC flags specific to Hardkernel Co's ODROID-XU SBC
+cflags_release+=(-mcpu=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_rpi1

@@ -0,0 +1,2 @@
+# GCC flags specific to the Raspberry Pi 1 series of SBC
+cflags_release+=(-mcpu=arm1176jzf-s -mfpu=vfp -mfloat-abi=hard)

scripts/automator/build/gcc-linux_rpi2

@@ -0,0 +1,2 @@
+# GCC flags specific to the Raspberry Pi 2 series of SBC
+cflags_release+=(-mcpu=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_rpi3

@@ -0,0 +1,4 @@
+# GCC flags specific to the Raspberry Pi 3 series of SBC
+cflags_release+=(-march=armv8-a+crc -mtune=cortex-a53 
+                 -mfpu=neon-fp-armv8 -mfloat-abi=hard)
+

scripts/automator/build/gcc-linux_rpi4

@@ -0,0 +1,3 @@
+# GCC flags specific to the Raspberry Pi 4 series of SBC
+cflags_release+=(-march=armv8-a+crc -mtune=cortex-a72 
+                 -mfpu=neon-fp-armv8 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_tinker

@@ -0,0 +1,3 @@
+# GCC flags specific to the ASUS Tinker Board SBC
+cflags_release+=(-marm -march=armv7-a -mtune=cortex-a17 -mfpu=neon-vfpv4 
+                 -mfloat-abi=hard)

scripts/automator/build/gcc-linux_vero4k

@@ -0,0 +1,2 @@
+# GCC flags specific to the OSMC Vero 4K SBC
+cflags_release+=(-mcpu=cortex-a7 -mfpu=neon-vfpv4)

scripts/automator/build/machine-vero4k

@@ -0,0 +1,3 @@
+# Universal flags specific to the OSMC Vero 4K SBC
+cflags+=(-I/opt/vero3/include)
+ldflags+=(-L/opt/vero3/lib)

scripts/build.sh

@@ -9,10 +9,11 @@
 # If run without arguments, the script asks for required arguments one
 # by one, which includes the above two (--compiler and --build-type).
 #
-# Optional arguments include the version of compiler and additional
-# build modifiers such as link-time-optimizations (--modifier lto),
-# feedback-directed-optimizations (--modifier fdo), and taking advantage
-# of the building-machine's full instructions sets (--modifier native).
+# Optional arguments allow specifying the version of compiler,
+# machine type, and applying build modifiers such as:
+# - link-time-optimizations (--modifier lto),
+# - feedback-directed-optimizations (--modifier fdo)
+# - current processor instructions sets (--modifier native)
 # All modifiers are available simulatenously.
 #
 # Usage examples:
@@ -25,6 +26,73 @@
 #
 set -euo pipefail
 
+# Detects the machine type and sets the 'machine' variable
+function query_machine() {
+	# Start with a sane and safe default
+	machine="$(uname -m | sed 's/-.*//')"
+
+	# Only attempt further detection on Linux-based systems
+	if [[ ! -f /proc/cpuinfo ]]; then
+		return
+	fi
+	# ARM differentiation based on
+	# https://github.com/RetroPie/RetroPie-Setup/blob/master/scriptmodules/system.sh
+	case "$(sed -n '/^Hardware/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo)" in
+		BCM*)
+			# calculated based on information from
+			# https://github.com/AndrewFromMelbourne/raspberry_pi_revision
+			local rev
+			rev="0x$(sed -n '/^Revision/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo)"
+			# if bit 23 is not set, we are on a rpi1
+			# (bit 23 means the revision is a bitfield)
+			if [[ $((("$rev" >> 23) & 1)) -eq 0 ]]; then
+				machine="rpi1"
+			else
+				# if bit 23 is set, get the cpu from bits 12-15
+				local cpu
+				cpu=$((("$rev" >> 12) & 15))
+				case $cpu in
+					0)
+						machine="rpi1"
+						;;
+					1)
+						machine="rpi2"
+						;;
+					2)
+						machine="rpi3"
+						;;
+					3)
+						machine="rpi4"
+						;;
+				esac
+			fi
+			;;
+		ODROIDC)
+			machine="odroid_c1"
+			;;
+		ODROID-C2)
+			machine="odroid_c2"
+			;;
+		"Freescale i.MX6 Quad/DualLite (Device Tree)")
+			machine="imx6"
+			;;
+		ODROID-XU[34])
+			machine="odroid_xu"
+			;;
+		"Rockchip (Device Tree)")
+			machine="tinker"
+			;;
+		Vero4K|Vero4KPlus)
+			machine="vero4k"
+			;;
+		"Allwinner sun8i Family")
+			machine="armv7_mali"
+			;;
+		*)
+			;;
+	esac
+}
+
 function parse_args() {
 	# Gather the parameters that define this build
 	postfix=""
@@ -36,19 +104,32 @@ function parse_args() {
 		-t|--build-type)        selected_type="${2}";          shift 2;;
 		-m|--modifier)          modifiers+=("${2}");           shift 2;;
 		-p|--bin-path)          PATH="${2}:${PATH}";           shift 2;;
+		-a|--machine)           machine="${2}";                shift 2;;
 		*)                      configure_additions+=("${1}"); shift;;
 	esac; done
 
-	# Import our settings and report missing values
-	machine="$(uname -m | sed 's/-.*//')"; import machine "${machine}"
-	os="$(uname -s | sed 's/-.*//')"; import os "${os}"
+	# Determine and import machine-specific rules
+	if [[ -z "${machine:-}" ]]; then
+		query_machine
+	fi
+	import machine "${machine}"
+
+	# Determine and import OS-specific rules
+	os="$(uname -s | sed 's/-.*//')"
+	import os "${os}"
+
+	# Import compiler rules, plus any OS + machine customizations
 	import compiler "${compiler:-}"
 	import "${compiler:-}" "${os}_${machine}"
-	if [[ -z "${selected_type:-}" ]]; then arg_error "--build-type" "${TYPES[*]}"; fi
+	if [[ -z "${selected_type:-}" ]]; then
+		arg_error "--build-type" "${TYPES[*]}"
+	fi
 
 	# Create a pretty modifier string that we can add to our build-type
 	printf -v mod_string '+%s' "${modifiers[@]:1}"
-	if [[ "${mod_string}" == "+" ]]; then mod_string=""; fi
+	if [[ "${mod_string}" == "+" ]]; then
+		mod_string=""
+	fi
 
 	# Print a summary of our build configuration
 	underline "Compiling a ${selected_type}${mod_string} build using "`